Can you put Zyra, Karma, and Brand in the same Mana Regen tier as all other Mages?
Zyra, Karma, and Brand have 2 more base Mana Regen than all other Mages.
Give them 6 Mana Regen at level 1 instead of 8. That way they would be in line with Xerath, Ziggs, Vel'Koz, Viktor, Veigar, Annie, Anivia, Ahri, Swain, Syndra, Twisted Fate, Karthus, Heimerdinger, Elise, Fiddlesticks, Cassiopeia, Diana, Nidalee, Orianna, Kassadin, LeBlanc, Lux, Malzahar, Azir, Aurelion Sol ... ... basically all other Mages.
For those interested, the other exceptions I found were Lissandra who has the least amount of Mana Regen in the game (because of her passive?)(0.33 and 0.4/level less), Taliyah has slightly more (1 and 0.05/level more), Ryze has more per level (0.2/level), and Morgana and Zilean start out with more (2.5 more at level 1).