Depends, for strict boss killing setup with 2h weapon, it makes sense in places where you can't use deathgaze (for example astrogha where you gonna kill totems with deathgaze).
Reists of those bosses goes to 70, so you want to have combined -170 vs them to put them at effective -100.
Thing to note, wolf companion curse will not work with iceburst (because you don't deal any physical damage in order to trigger it). This makes it not worth using with our core build, only later with 1pt wolf companion specs.
Generally I like deathgaze more, wherever it can be used. Maxing iceburst is definitely worth if you gonna use it vs certain boss, because pierce per point is definitely good value for this skill.