A Veteran GM's First Impressions of D&D 4th Edition
Having made a 4e character and played through the combat system, and having played and DMed 3.0/3.5 since it was released, I think this is the best way of summing up my thoughts:
4e is like getting a meal at a chain restaurant - it might taste good and always be consistent, but it won't have the unique attributes that can be given by a good cook at home. 3.5e is the home-cooked food - it can be good or bad depending on the cook, but the flavors can vary more widely.
4e thus far is alost cookie-cutter in character generation. All first level characters of a particular class are practically identical. Skill-wize, almost anyone of a given level is identical. At least with the old skills system you could have, say, a specialist in something like knowledge(cartogaphy) or other random skill and were utterly clueless when it came to other skills. This actually came up in a campaign a while back - the party needed to figure out where we were going and make a map, and my wife's character had ranks in knowledge(cartography). This almost dumbfounded the DM, who had not expected that, and the map was created much easier than he expected.
Also, I can't see any reason why a 4e 10th lvl wizard should be better than a lower-level trained fighter at athletic skills. Tying everything to level is just power inflation. Characters with weaknesses are the most fun to play, and no one should be uber at everything.