Tables of mp5 regeneration per level post weed patch (4.20)
4.20 is changing the way mana regeneration works. patch notes
This table shows the new base mp5 of (Ahri, Alistar, Anivia, Annie, Azir, Blitzcrank, Braum, Cassiopeia, Diana, Elise, Fiddlesticks, Fizz, Galio, Gragas, Heimerdinger, Jayce, Karma, Karthus, Kassadin, Kayle, LeBlanc, Leona, Lulu, Lux, Malzahar, Morgana, Nidalee, Orianna, Ryze, Swain, Syndra, Taric, Thresh, Twisted Fate, Veigar, Vel'koz, Viktor, Xerath, Ziggs, Zilean, Zyra) and It compares it to Lux's old mp5 per level. http://i.imgur.com/jHyqn7C.jpg Basically early game is the same till level 8, then a slight buff after that that grows into a noticeable difference end game.
However, the mana regin items where very heavily nerved early game.
This table shows the mp5 gains of from items for the champs listed above.
http://i.imgur.com/xb2A6zf.jpg
MANA REGENERATION +3 mp5 ⇒ +25% base mana regeneration (used to be a bad buy, now it's twice as bad)
MANA REGENERATION +8 mp5 ⇒ +60% base mana regeneration
MANA REGENERATION +6 mp5 ⇒ +25% base mana regeneration
MANA REGENERATION +7 mp5 ⇒ +50% base mana
MANA REGENERATION +10 mp5 ⇒ +50% base mana regeneration
MANA REGENERATION +10 mp5 ⇒ +100% base mana regeneration
MANA REGENERATION +20 mp5 ⇒ +100% base mana regeneration
I think this change is a big win for mid lane manaless champ, because mid lane mana users are going to have a lot less of the blue stuff.
Seems like AP mages will now only buy Morellonomicon for mana, cast less spells, and beg for blue buff every time. God help you if your jungle needs it, because without chalice there is no other early game mana item that justifies the cost.
Tear and Chalice are so bad now I don't think they will be built. by the time they do any think you will gimped your power curve way too hard by investing them.