Sona burns out her mana too fast even in late-game since Mana Font was nerfed
Sona only ends up with around 16 base mana regen and 1106 maximum mana at level 18. Considering that her heal costs 100 mana, along with her other costs (200 mana ult anyone?), she has RAPID burnouts even if she builds a lot of mana regen or a Mikael at level 18.
This needs to be adjusted, IMO, or playing as Sona is going to quickly become unsatisfying. I mean, look at Janna; she gets around 1500 maximum mana at level 18. Why does she get the good amount while Sona and Nami get the short end of the stick?
I recommend increasing Sona's maximum mana at level 18 to something more reasonable. 1106 is not nearly enough.
"Why buff Sona?! STFU!"
Because if she's burning mana too rapidly, it takes a lot out of her decision-making. She's not able to keep fighting for any lengthy period of time, which is something supports are SUPPOSED to be able to do. If Sona's constantly going to be out of mana, what decisions are there to make? None, really, except run to her death.