On the note of mgs2. The way it was done on the ps2 will not let it be done on the dreamcast or even the xbox for example. If you code to the systems strengths (like mgs2 was done ) And targeted at the dreamcast you would get a game that looks just like mgs2 with all its game play and most of its effects and then some effects that weren't in the ps2 version i.e bumpmaping .
No. If MGS2 was coded to the DC's strengths, you'd probably have a major decrease in geometry and effects. On the other hand, textures would probably improve because of bump mapping. Then of course image-quality, but I doubt that could be improved much. In other words, you'd have a game that would look completely different.
As good as Shenmue may look, don't you at least realise how it runs on it? Sub 30fps, chocks here and there, pop ups etc. At least MGS2 maintains double and constant framerate throughout the game. I seriously am boggled as to why you seriously believe DC could handle it. Once they start cutting down things in favour of performance, it just wouldn't look the same anymore. It'd be a different game - a different experience. There's simply no comparasment.
Bump mapping and in average better image-quality is hardly a subsitute for the lack of geometry and fillrate that the PS2 can push.