Some talents need to be buffed or reworked, the latter half of the left side of the Frost tree is just dead talents.
GS/ROF are special cases, they both hit pretty hard already for a single ability, they defintely need a buff to make them usable in PvE but Blizz will have to make sure they don’t hit too hard in PvP.
Glacial is situationally, kind of, sort of, used occasionally from time to time in PvP. When you’re left alone to actually pump them out that is, which is not often. But thats more because theres not really anything worth picking left. The rest of the talents are trash, and Glacial is the least trash of them so it’s a “meh, i guess i will pick it”, and then most likely not use it very much cause you aren’t able to.
I think that depends on what kind of PvP you do. I bet it’s difficult to find openings to cast spike in high level arenas, but in random battlegrounds and lower ranked arenas, there are opportunities to use it. I guess you could say that those do not matter, but to the players in those games, it does.
Therein lies the trouble, balancing abilities for everybody.
Perhaps they should have different damage auras for Arena, open world PvP/BGs and PvE, rather than the current PvP/PvE. It would probably be a right ballache to do it well but it would make the game better in the long run.
That’s one of Frost’s biggest issues, we do actually have AoE talents - Glacial Assault/Comet Storm/Cold Front but you can’t take them without severely hampering your ST/cleave damage.