That's true. Despite being a pretty significant threat during the first season, Icy, Darcy and Stormy were really weakened during the later seasons, especially season three where the girls could easily defeat them. Granted, it probably helped that they continued to get new power-up items/forms to increase their powers and they probably wanted to make the new villains stand out as being more threatening and powerful than they are, but it still make the three witches look like pretty weak villains.
Outside of the three movies and a few episodes that didn't didn't focus on Bloo that much either, I couldn't get into the show either. There was just too much focus on such an unlikable character that I didn't really enjoy the show most of the time I did watch it. I think that they made that change to add some more conflict for the show, especially since the ending to the pilot made it sound like everything was all worked out, but I think that they also could have made him more likable and made it clear that he actually liked his friends instead of just using them to get what he wants most of the time.
I'm not sure if Rigby was that likable at the start. Maybe he wasn't as cruel with ruining Mordecai's chances with Margaret like he is now, but I thought that he was still pretty selfish, ungrateful and immature from the start. I'm not sure if he's worse than Bloo in that regards since it's at least clear that he does like hanging out with Mordecai. He's just too immature and selfish to understand that Mordecai's feelings for Margaret. It probably also help that Rigby has been a jerk from the start, unlike in Bloo's case, and that I haven't been completely turned off from watching Regular Show after seeing how incredibly selfish and annoying Rigby can be like I did with Bloo.
As for Benson, I don't think he's a terrible boss. He might be yelling too much to be considered a really nice boss, but considering the amount of time Mordecai and Rigby goof off and avoid doing the work he gives them, it's kind of understandable that he would yell at them and why he doesn't treat them with respect. If they aren't going to be good employees, then I don't see why Benson should be really nice to them. Besides that, he doesn't seem to hate them, despite how they avoid most of their work. He clapped for them during that open mike night, even though they admitted that they were lip synching, wasn't mad at them for taking yet another break after they helped him get his job back and even in last week's episode, told them that they did a great job with the horror movie in the graveyard, although part of that was because they brought some people back to life as zombies by mistake, and gave them a paid day off. It sounds more like Benson actually improved as a boss, or at least in his relationship with Mordecai and Rigby, instead of getting worse to me.
I didn't think Misty was that bad to Ash. She was kind of harsh on some of his rookie mistakes, especially when she herself was barely more experienced than Ash was at the time, but she did become his friend during the course of the series and practically forgot about her old broken bike that she constantly reminded Ash about during early Kanto. As for Charizard, it did have an attitude problem that really came out of nowhere if you look back at the first season and it most likely was a way to prevent Ash from just using Charizard in all of his matches, as well as show how much of a rookie he still was. Still, its attitude did improve during the Orange Island and it actually learned to respect Ash again, so I don't see how it got worse during the series. Max actually didn't really bother me that much. I thought he was annoying during his first few appearances where he did act like he knew so much more than Ash, despite not having any experience as a trainer himself, but I don't think he was that bad at all. He was fairly likable and it was interesting to have a main character with no Pokemon of his own for once.
I do agree with you about the serious Team Rocket. The concept of the Team Rocket trio being more serious and competent sounds like an interesting idea, but I don't think that the execution works for the show. They just feel extremely dull, haven't really done anything that's more impressive than what they did as comedy relief and their one minute of screentime in each episode doesn't help to make me feel engaged in their plot. As for Iris, I actually think her attitude towards Ash is improving as they continue to travel with Cilan. I thought that she looked fairly impressed with his victory at the first Unova Gym, she did hint at how Ash would defeat her in battle when he asked her for match after her training with Axew didn't go well, even though she had constantly called him a kid during most of the previous episodes and she's been pretty supportive for Ash with offering some suggestions after his losses to Trip and Lenora. Though, most of that advice she does need to take herself given the skill of her Axew. I usually don't get too upset at Iris for calling Ash a kid, unless its about something from Unova that he obviously wouldn't know. Even though he does have quite a bit of experience under his belt, Ash certainly doesn't act like he does and I could see how that first impression of Ash might be hard for Iris to ignore. Besides that, I think it's supposed to be funny since Iris acts like a kid as well.
Outside of the three movies and a few episodes that didn't didn't focus on Bloo that much either, I couldn't get into the show either. There was just too much focus on such an unlikable character that I didn't really enjoy the show most of the time I did watch it. I think that they made that change to add some more conflict for the show, especially since the ending to the pilot made it sound like everything was all worked out, but I think that they also could have made him more likable and made it clear that he actually liked his friends instead of just using them to get what he wants most of the time.
I'm not sure if Rigby was that likable at the start. Maybe he wasn't as cruel with ruining Mordecai's chances with Margaret like he is now, but I thought that he was still pretty selfish, ungrateful and immature from the start. I'm not sure if he's worse than Bloo in that regards since it's at least clear that he does like hanging out with Mordecai. He's just too immature and selfish to understand that Mordecai's feelings for Margaret. It probably also help that Rigby has been a jerk from the start, unlike in Bloo's case, and that I haven't been completely turned off from watching Regular Show after seeing how incredibly selfish and annoying Rigby can be like I did with Bloo.
As for Benson, I don't think he's a terrible boss. He might be yelling too much to be considered a really nice boss, but considering the amount of time Mordecai and Rigby goof off and avoid doing the work he gives them, it's kind of understandable that he would yell at them and why he doesn't treat them with respect. If they aren't going to be good employees, then I don't see why Benson should be really nice to them. Besides that, he doesn't seem to hate them, despite how they avoid most of their work. He clapped for them during that open mike night, even though they admitted that they were lip synching, wasn't mad at them for taking yet another break after they helped him get his job back and even in last week's episode, told them that they did a great job with the horror movie in the graveyard, although part of that was because they brought some people back to life as zombies by mistake, and gave them a paid day off. It sounds more like Benson actually improved as a boss, or at least in his relationship with Mordecai and Rigby, instead of getting worse to me.
I didn't think Misty was that bad to Ash. She was kind of harsh on some of his rookie mistakes, especially when she herself was barely more experienced than Ash was at the time, but she did become his friend during the course of the series and practically forgot about her old broken bike that she constantly reminded Ash about during early Kanto. As for Charizard, it did have an attitude problem that really came out of nowhere if you look back at the first season and it most likely was a way to prevent Ash from just using Charizard in all of his matches, as well as show how much of a rookie he still was. Still, its attitude did improve during the Orange Island and it actually learned to respect Ash again, so I don't see how it got worse during the series. Max actually didn't really bother me that much. I thought he was annoying during his first few appearances where he did act like he knew so much more than Ash, despite not having any experience as a trainer himself, but I don't think he was that bad at all. He was fairly likable and it was interesting to have a main character with no Pokemon of his own for once.
I do agree with you about the serious Team Rocket. The concept of the Team Rocket trio being more serious and competent sounds like an interesting idea, but I don't think that the execution works for the show. They just feel extremely dull, haven't really done anything that's more impressive than what they did as comedy relief and their one minute of screentime in each episode doesn't help to make me feel engaged in their plot. As for Iris, I actually think her attitude towards Ash is improving as they continue to travel with Cilan. I thought that she looked fairly impressed with his victory at the first Unova Gym, she did hint at how Ash would defeat her in battle when he asked her for match after her training with Axew didn't go well, even though she had constantly called him a kid during most of the previous episodes and she's been pretty supportive for Ash with offering some suggestions after his losses to Trip and Lenora. Though, most of that advice she does need to take herself given the skill of her Axew. I usually don't get too upset at Iris for calling Ash a kid, unless its about something from Unova that he obviously wouldn't know. Even though he does have quite a bit of experience under his belt, Ash certainly doesn't act like he does and I could see how that first impression of Ash might be hard for Iris to ignore. Besides that, I think it's supposed to be funny since Iris acts like a kid as well.