Zyra has almost twice as much base mana regen at lvl 1 as a normal mage.
- Most mages: 8
- Most enchanters and Kayn (tied for the second highest in the game) : 11.5
- Zyra: 15.335
Even when taking scaling into consideration, Zyra still ties for 8th highest base regen at level 18." What's your point?", some of you may ask. There are two major problems with this:
- Despite the fact that as a support she doesn't have to use spells to farm, she can cast way more before going OOM than a mid lane mage. She isn't punished nearly as much as most mages for mindlessly spamming.
- Since the last mage item rework Riot decided to shift mid lane mages towards relying on flat mana and the Lost Chapter passive for mana sustain in lane, while % base mana regen was made a stat primarily used on support items.
This ultimately means that Zyra synergizes more with support items than actual mage items, which is likely a contributing factor to Zyra not being preferred mid; 
is simply a better item on her than 
EDIT: Since people here seem to be unable to grasp nuance, I'm not saying Zyra is OP, I'm saying that her base regen is part of why she is preferred support over mid because of how itemization for both roles works. She needs power shifted away from that stat torwards something else if Riot actually wants her to be a mid laner again.
high mana reg I want at least 20 per 5 for 
. My biggest issue is that most of her damage comes mostly from her plants dps and less from her actual skills. She needs a higher skill cap that revolves around her actually landing her skills, instead of hit some seedlings in the backline and let them focus whoever they hit.
