Ah, I've only seen the Rurouni Kenshin film in terms of live action adaptations, so I have no idea
One of the more prominent ones that should have easily been done was Initial D. It was a horrible, horrible mess. Blood wasn't too bad, but strayed from the original story and was nowhere near the level of the original OVA. Death Note was fairly blah, Shinobi, which was an adaptation of Basilisk, was laughable with how badly it messed the story up. The fight scenes were pretty good, but past that....
Cutie Honey was one of the more hilarious live action ones as well, just with how ridiculous everything ended up looking :)
One of the few anime characters I've seen pulled off well in Live Action, ironically enough, is the NA version of Guyver, but not the first movie, the second one. The suit they made in that for Guyver was amazing. Plus, lots of people love it since Sho is played by David Hayter, aka Solid Snake.