Kenshin overrated? Honestly, I don't feel that way about it. Keeping in mind that I initially didn't like this show when it aired on Toonami, I could at least respect it for what it was. When I finally got a chance to re-watch it, I actually loved it, up until the end of the Kyoto arc. After that, the fillers dragged the TV anime's quality down.
As for the OVA's, I honestly enjoyed Trust and Betrayal. Sure, it lacked the mixture of humor and drama that both the manga and TV series had, but considering that it was only covering Kenshin's past, its serious and grim tone fit, since the manga was just as serious and dark during that portion of the story. The Reflection OVAs, on the other hand, were just pure mellodramatic crap, IMO.
And as for the manga....well, personally, I find it to be Watsuki's masterpiece, myself. And what's more surprising is that I have not been able to get into a single one of his other series. They all seem so ridden with cliches, or uninspired, compared to Kenshin, which actually just surprised me, knowing that they were all from the same mangaka.
Anyways, I feel that Kenshin is one of those series that gets just as much respect as it deserves. Its definitely not as overhyped as other popular Shounen Jump series that I have seen, and its also not underappreciated, either. It just has the right amount of praise, and that's why I personally don't see how its overrated. But, I suppose it all depenRAB on how much enjoyment you personally get out of the series.
As for me, I love the manga. Its easily the best action-oriented Shounen Jump manga that I have ever read. As for the anime, I do enjoy it, but due to its heavy amount of filler and lack of the Jinchuu arc, it pales in comparison to the manga, for me. Still, its a great series, and honestly, the only other 2 action shounen series which I like as much, or even a little bit more, than it, are Yu Yu Hakusho and Hunter X Hunter, since Toriyama is even more awesome than Watsuki. I also enjoy Toriyama's Dragon Ball and Oda's One Piece, but neither series have been able to come close to impressing me with their story-telling and character development elemnts more than Rurouni Kenshin has.