Might wanna do something about Frost Queen's, Riot
You don't want mages to have mana regeneration as a free stat. You want mages to have to carefully manage their mana at all stages of the game, in return for the vast amount of power and utility they can bring.
And honestly? I can agree with all of that, no problem here. If the likes of Xerath and Lux have to be patient with their spells or be forced to back more frequently so I can breathe, I'm all for it. But from what I'm seeing so far, people don't agree.
Granted I've only done two three on the new patch so far, but in two of those matches I saw the Frost Queen's Claim item line on pretty much any mana-gated AP user. This statement might be pre-emptive, but Riot, might wanna do something to keep it from ending up central on every AP-central mana user in the game and warping the balance around its presence. Maybe something like "Mana regen when within X range of allied champion" or something?