Tbh though, not getting W until you have to is an old way of thinking, where it wasn't worth the mana cost for the dmg... but that was when blue build wasn't basically the only ADC build for him, and new masteries didn't exist. But once you have a tear (not to mention tear + sheen), not only do you have the mana to use it pretty often - it actually helps to spam your tear stacks, gain more fervor, and stack your passive quicker. It also does do a (sort of) decent amount of additional damage in the form of magic, poke thru minions, and the steroid helps in taking objectives.
Taking W at lvl 4 or so adds all of that, in place of some additional E dmg that you mostly shouldn't be using for damage anyway (as AD Ezreal). I'm not saying everyone should start grabbing W early on again, but it's not really a bad thing to do nowadays either...
Although, if they were to make a changes to him, increasing the base damage on his W, without changing any of his ratios at all or without nerfing his Q, would be an acceptable one I guess... That way AP Ezreal's early game is a bit stronger, and AD Ezreal has more reason to take it when he should. Then again I'm an Ezreal main, I play him both AP and AD, buffs are welcome... so long as there aren't any crippling nerfs in the future as a result, particularly that of his AP ratios (or ANY nerfs period, since like I said he's in an ok enough spot now, as far as I'm concerned...).