Originally Posted by
Serene
In all honesty it depends on how serious your guild is about progression.
Waiting until numbers pass to confirm this, but Fire will likely be world-leading progression spec unless it gets heavy nerfs. Frost will be viable for more casual guilds (not meaning that to be JUST casual guilds, though) and at the moment, Arcane isn't really viable, even with Ice Floes and even with buffed RoP, it's not "bad" and it will output damage when played correctly, but it'll be too much hassle.
Fights like Juggernaut where you're being knocked back periodically for an entire phase, or Blackfuse where there's so much movement from shit on the floor, or Immerseus where you're forced to constantly re-place RoP, it just won't work. These three are just examples, there are more fights which are similar.