Several factors in MechWarrior 4 contributed to an underwhelming MechWarrior experience:
The Mechs moved very agile and fast, not like a 30 to 100 ton coloss would move.
So, what? The mechs in MW2-3 moved like Urbies in MW4? The game wasn't all that fast, and I don't see how making it slower would improve the fun. This seems like one of those areas where gameplay trumps realism.
The Mechs were very colorful, unlike you would expect a 30 to 100 ton death machine would look.
The Mech's textures had no details at all, unlike in MechWarrior 3 in which the Mechs looked like actual Battlemechs.
I looked up and compared some screenshots of MW3 and MW4. I think I can see what you're talking about, but it's a subtle difference. More details might be nice, but I'm a fan of minimalist designs and the MW4 look really appeals to me. The new video was pretty spiffy, though.
Also, who hasn't wanted to rampage across the battlefield in a pink Fafnir?
Simulation was more simplistic, very flat Mech configuration.
Overall, this made if feel more "arcade".
I suspect this last part is something I just won't understand without playing the earlier games. I'm not familiar with how customization worked in MW3, but I really like the weapon slot system in MW4. It's way better than the "You can have 8 of any weapon you want regardless of chassis" system used in the SNES MW1. Dark Wing Lance, meet SRM-spamming Noobler Nexus o' Doom!
It'll be interesting to see how the new game works out. I'm a bit worried by all these references to the 360, as I don't want the game to be dumbed down just so the Xbox kiddies don't get jealous. I also didn't see anything about mech customization in the interview, and the "experience for using the same mech" thing could be a problem. Encouraging mech specialization is fine, but I don't want to get kicked from multiplayer games just because I don't have the Advanced Catapult Piloting skill or a level 6 PPC Aptitude.