The BIG hit to wizards is the (finally - we knew it was coming) change so that weapon focus no longer works on implements. That's a 1/2/3 damage reduction right there.
Yeah. 1/2/3 on an area effect can be 3/6/9. Not that Wizards cannot find boosts to damage other ways (Dual Implement Spellcaster which is 1/2/3/4/5/6, Destructive Wizardry 2/3/4, etc.).
I'm not seeing that they were nerfed that badly here, especially considering that not every Wizard used to take Weapon Focus (some Wizards actually used Orbs or Wands or Tomes

).
I've always thought of wizards as sort of off-strikers, but frankly I'd hesitate to say that much anymore. To me, wizards had the problem of having amazing dailies and horrid encounter powers, so hopefully this will fix part of that problem.
I do see this new concept of "many Wizard encounter powers having an effect on a miss" as watering down feats like War Wizardry for Wizards (but not watering it down for Sorcerers).
I never considered Wizard Encounter powers to be horrid. They just aren't heavy damage or especially great control. But, they aren't horrid. Icy Terrain in round one could take away an attack by multiple foes for an entire round in addition to doing some damage to multiple foes. How is Icy Terrain hitting two foes for a total of 7 damage each and taking those foes out for a round horrid whereas a Fighter's same level Spinning Sweep hitting two foes for a total of 8 damage each and only knocking them prone good?
The main problem with Wizard powers is that most of what they can do with control powers, some other non-controller classes can do and Sorcerers do more damage with all powers. Wizard's Control Fu is sometimes weak grasshopper unless they are using a Daily power.
Yeah the game-changing dailies rock, but Ashir, my L4W wizard struggles to find a level 1 encounter power to use regularly. The encounter power selection is pretty weak.
I don't know what At Will powers Ashir has, but Grasping Shadows on the Fighter marked foes in the front line combined with Phantom Bolt (or even Thunderwave) can be nice.
Charm of Misplaced Wrath is pretty nice too, although it is not multiple targets.
I think the real issue is that some classes in the splat books have powers that are just a tad bit nicer than classes in the original PHB. So, people compare and suddenly find some of the original classes to be a bit lacking.