The models already don't match up. They don't even match up in game!
Look at Manny's hands as he goes over the brochures in the opening sequence, and then look at them towards the end of the game.
Also, look at Manny's hands when you get something out of his suit (the close up screen) and then look at them in-game proper.
Increasing the polygon count would look great... smoothing off some of the uglier edges, giving Glottis a mouth without holes in it etc. That's all I'm talking about.
Sadly nothing can be done about the cut-sequence inconsistencies