First things first, I got a shout out, made even cooler by the fact that I did not actively do anything to get it. While I had been aware of the RPG Carnival, seeing it here and there, though I am going to make a greater effort to follow it (as well as get featured).
Anywhoo according to the transcript from the Class Design seminar wizards are, at least currently, like 3rd Edition wizards near the end-run; they rely heavily on "Vancian" magic, but can take spell feats that give them at-wills, which remind me largely of Reserve feats from Complete Mage. While I am not a fan of daily resource management, at least rituals seem to still be intact. Rituals are great because it allows me to drop scrolls in adventures that anyone could use (which I did in the first A Sundered World session), as well as provide some flexibility to anyone that wanted to invest a feat.
One upside is that there is supposed to be a kind of "trade-in" mechanic, though I am not sure if it will allow wizards to cash in lower level spells for a higher one on the fly or as they level up. I know that somewhere it was said that fireball would deal a set 5d6 damage, and if you want to make it better you would slot it into a higher level. I like this idea because it would help greatly reduce the "power bloat". Some 4E powers did this, but not all, and I think that would allow a player to keep an iconic ability around without having to find another that works "close enough".
At least Bruce is on record for saying that they want classes to feel and play differently. In 3rd Edition wizards and sorcerers were too similar, what with sharing the same spell list. Though they tried to play up the bloodline angle later on with feat trees, it was not enough to diversify them. I feel that even 4th Edition did not go far enough, and I found it very difficult to properly evoke some sorcerer spell sources (especially dragon, which was the concept I theoretically should have enjoyed the most).