That's pretty much what I would presume. I personally have no problem with that, if a show has a nice story, then I'll watch from the first episode and play catch-up up I need to (like I did Full Metal Alchemist and Naruto: Shippuden). It just seems writers/executive think most people won't, or are too lazy, so they don't bother. Personally, I don't think anyone should dumb down their story out of fear of alienating new watchers, but it's a big problem with the industry I suppose. (Comics have written themselves into that corner already, always toting how something is 'a perfect jumping on' point)
Sure, every episode is a story, but it's broken down and restricted so much. Emphasis on 'some'. You can pretty much cheat the ending by looking at the clock (if the episode is almost over, the good guys are going to win).
Granted, maybe it's more of the fact they're not made with an actual ending in mind so the development doesn't push for that purpose rather than being episodic, but they pretty much go hand in hand with these kinds of shows. Or maybe it's just the writers. Our sample size is a bit small so it's hard to dissect and analyze where the problem lies.
I never found her tragic because I knew it wasn't an issue they were going to address or ever develop, and they never did. It was played for jokes more than anything (I know he's the Joker, but still). If the writers don't go anywhere with the character, then there's not much point in placing emotional value on them. Not when I can place it on more deserving characters like Maes Hughes or even Dinobot.
For example, half the time we get a Harley/Ivy episode we get some passing mention of "She had a fight with the Joker so she's staying her". We don't really see it, and it's just a passing line there to set up a Harley/Ivy team up episode, not really develop her character since there's no lasting consequences with that fight. Compare that to, say, Hawkgirl's betrayal, we see that go down and how it plays out in Justice League, and by the next episode everything just isn't back to normal for her. It's a developing part of her character that lasts until the end of the show. Harley? It's barely development for one episode before it gets written back to status-quo.
The thing is that bare-bones continuity is just about all we get most of the time. Some passing mentions that episodes have happened, but no real endgame conclusion or story on the horizon to wrap anything up. Sure, Mr. Freeze deteriorated (for the worse) as a character, but that ended up hurting him because the writers had no idea what to do with him; being more story focused (like, making it a 52 episode series) would probably alleviate that.
What one finds good and one finds bad is entirely subjective, though, so you might as well make the most of the series and structure it so it has much potential as possible.
Because anyone can go back years later and wrap stuff up from an old show when the show has already been over and cancelled and they know they missed the chance to end things.