Morgana's mana costs seem too low to me...
Been playing a bit of morgana lately, just in norms. used to play her all the time.
Wanted to check out her new W and stuff. And wow. She's quite oppressive in lane. Almost as bad as malzahar.
Nearly infinite mana on nearly instant wave clear. I have routinely been 40-50 CS up on my opponent, and once I get an item or 2, I can pretty much kill them for free with flash + W + R + Ignite or Q + W + R + Ignite.
Combine that with almost complete immunity from ganks via her spell shield, and she's pretty strong ATM. And honestly I think it all stems from the fact that her mana costs are basically non existent.
But hey... that's just one gold player's opinion.