But DirectX 9, OpenGL or anything like this isn't a server sided mod. So it hasn't anything to do with MP.

And yes, AA would be great. Bump Mapping could be cool if you're walking over a wood based ground like the in first level of Deus Ex.
Why pump this old game instead remaking it? This is easier said than done, dude.
- You would have to create the game from scratch.
- You would need a complete team (programmer, graphicans, Sound and Music composer etc.)
- This would take a LOT time.
- You would have to announce it and make the people know about it. (Not that hard in Deus Ex Scene ...)
- It's just easier to pump an old game instead of recreating it.