IMO the current system is clumbsy where it saves your recently used chat setting, example: You type to Everyone but then it doesnt change back to ally chat, instead you have to manually do this.
As player = Enter - Ally Chat, Shift-Enter - All chat.
As spec = Enter - Spec Chat, Shift-Enter = All chat.
This is the system used in StarCraft.
The AltGr key is awkward to use. From my own perspective i have FN key just beside and its very likely i missclick.