Here's my take on 4e Wizards vs. earlier versions.
Like everything in 4e, it will be difficult for players who want old D&D mechanics. The new game has old D&D feel at times, but I believe players will have more fun if they think about 4e as new game, not an extention of the old.
4e wizards are certainly more balanced, as are all of the classes. One of the biggest problems with past editions was that playing a 1st, 2nd or 3rd level wizard was not so exciting. It meant avoiding combat, often running out of spells and resorting to complete support roll for a number of encounters unless the group was ready to rest for the day. On the other hand, at higher levels spells were devastating, if opponents failed saving throws. That's a big "if".
In 4e, wizards can feel more a part of the party in every encounter, plus, they can always do something that is more thrilling than firing an ineffective crossbow bolt after all spells were depleted.
I do agree that there is less creativity in spell selection and use in 4e, but perhaps, 4e wizards can use Arcana, History, Dungeoneering more to roleplay the brainy problem solver. Additionally, at-will spells like ghost sounds and mage hand, can be used creatively. Also, like some others have said, as more rules and supplements are added, there will be more utility spells and other creative spells or rituals that will add more creativity to the spell casting.
The bottom line for me is that I cannot say 4e wizards are better or worse, more fun or less fun to play. They are different.
Cheers