No, of course not.
Nope, that's not my interpretation.
So, you agree that RAW does not support actions (outside of OA or Interrupts) that can be used mid-other actions unless the action states that it can (like the Free Action Elven Accuracy)?
That was my only point. That RAW does not support using Wand of Accuracy mid-attack. I agree it should be done that way or WoA is lame, but I did not participate in a bizillion discussions on this and was going by RAW.
So going by RAW, Wand Wizards are weaker than the other two. Going by allowing WoA after the attack roll or even after the DM indicates whether WoA would work or not, it's still not that impressive.
Getting back to the OP's question, that's still less than one extra successful hit per encounter since there will still be encounters where it is not used.
If the Wizard attacks 15 times (i.e. 15 attack rolls, some of them probably area effect) in an encounter and his Dex bonus is +2, that's a 20.5% chance even with knowing exactly whether WoA works or not, that it cannot be used that encounter. At high levels with maybe a +5, this same 15 attacks results in almost a 99% chance that it can be used. But, this too is not guaranteed. The Wizard might not use it against a weaker foe, saving it for a greater foe or saving it for a Daily power and it might still never get used.
The real issue is whether it works when the Wizard needs it to work. Sure, it will damage a foe that would not have been damaged almost once per encounter. But, what if that is not the Daily Attack power? A few extra points of damage and possibly some control against a random foe (random being determined by whether it can work or not, the player does not decide, the dice decide) compared to an Orb Wizard where the Orb Wizard really decides whether the foe is worth using his Orb Power against (sure, he has to wait for a hit, but there are many hits in an encounter compared to just a few hits that WoA might work on). WoA still seems less useful.