Before it gave +140 AP after 7 kills, no matter deaths, and 70 of those AP, you got asap. Now it starts at 20 and slowly builds to 160, the mana steal and something else, not sure, plus you lose stacks on death. I feel it has been kind of a nerf.
Older one was much easier to charge. Now it's good if you stomp well and early, but given you're in an even game, it's not nearly as easy. Especially if you consider that being a nuker, you'll be probably squishy as hell and focused at first.
Been trying Ryze lately (haven't checked Annie yet, but that's not the point) and now I'm really not sure how to get a decent AP increase. Kassadin, Annie, Veigar, the few times I played Ryze, I'd usually get a Mejai. I guess I'll have to try the new one and see how it goes.