Originally Posted by Crazy Demon
Way to be a d0uche.
Though I do disagree with the item build and summoner spell choice, you mention a lot of advance techniques that I use as Annie. I remember rushing RoA when I was a new Annie but I haven't done it in awhile- I usually turn my catalyst into a Banshees for survivability to keep my stacks ( since I get mejai). Still, I'm willing to try it before judging.
It's worth mentioning that W doesn't go through some walls. After a little bit of experimentation, I've come to the conclusion that if you can't use Nidalee's pounce or Gragas's Bodyslamm to go through the wall, then W won't go through either. Not 100 percent sure about that, but its screwed me over before.
Like I said, you don't need a Mejai's to snowball. Getting kills will give you a gold and level advantage that should be all the snowballing you need. If you were to finish the game with 20 stacks then you would've won even if you hadn't bought that mejai's.
Rushing the RoA gives you a much stronger mid-game than the Mejai's rush does and you don't have to worry about losing stacks and can be a team player. In addition, it reduces your reliance on the golem buff in case your poor Kassadin might need it or something.
As for W, it will go through walls if the cast point (where Annie breaths the fire) is NOT over a wall/obstacle. You'll notice, for example, that if you're standing too close to a destroyed tower and try to cast W that it sometimes won't work. Take a few steps back and make sure she isn't casting over any obstacles and it should work fine.