The problem with the new Mana Font (Chalice passive): You need high mana for it to work properly
The fact that it restores a percentage of your missing mana every 5 seconds is, essentially, where I feel the problem is at. Unless you have 2k or more mana, that's not a lot of mana regen you're getting when you're low. Most mages who get Chalice don't also get Archangel's Staff, and thus the Chalice effect basically fizzles out on them.
I can't tell you how many times I was burned out of mana as Sona, Janna, or Lux in my last few games as them, even with a Grail. Back in S4, there was no such issue, but now it's a HUGE painintheass.
Riot, please tell us this isn't intentional.