The notes you linked are the total combined changes to the spell from mop to wod, the only thing they changed in either the previous build or the build before was the duration to 10 secs from 15 secs, the cooldown has been 90 seconds since the start of beta
I've seen some mages using Ice Nova, and it works as it says, but you really need Frost Bomb for damage.
frost bomb is currently doing around 45%-50% of frost mage damage in beta testing, compared to unstable magic / ice nova doing around 5%
its going to get absolutely slaughtered in damage tuning, then the other two talents on the row might see some more usage similarly with prismatic crystal, which is also strong in pvp because of how well it synergises with frost bomb
they have the mechanics currently to easily be the dominant caster at the start of wod, in terms of cc and burst - if sp rogue healer (holy paladin will probably be best) can survive the fotm reroll melee cleaves which we all have to look forward to, then it should be an extremely solid comp