http://www.xbox-360.fr/screens/top_spin_2/25.jpg
Top Spin 2 on Xbox 360
http://scr3.golem.de/screenshots/0301/virtua2/VTennis_ScrSht_04.jpg
Virtua Tennis 2 on PS2
You're right, the graphical jump is almost unnoticable, what are they thinking?
Folks, sure there's room left for improvement! But seriously, aren't you expecting way too much from every next-gen game? IMO it looks very good both technically and artistically and, as with most X360 titles, you'll probably have to see the game in motion on a real HDTV to truly appreciate the visuals.
Blake's (I assume that's him) character model looks awesome in that shot above IMO. Not all others are as impressive, but certainly nice enough. mckmas was salivating over the pants of the fighters in the VF5 thread, well Blake's socks look one hell of a lot better than those pants!
The environments are all very detailed and nicely done too, with a lot of variety in locations and backgrounds. They have a full squad of linesmen, refs, ballboys and a massive 3D crowd (just look at the huge centercourt). The main weakness is the lighting of the environments, it just isn't very realistic or visually impressive. Hopefully they'll do something about that before release, maybe they should have a little chat with Bizzare about their real-time ambient occlusion techniques.
Other than that it looks great and definitely next-gen. If the gameplay is anything like the original, this should be one sweet game!