My Ice/Staff is not as good as my SR/BS or my Shield/EM, perhaps, but I wouldn’t say it sucks. I run Ageless Radial on it to pad the DDR and it’s usually pretty tough. The silver lining to a Fire weakness is that it’s the most plentiful type of Res/Def set bonus. If you get Permafrost, Might of the Tanker procs, and other fire-related bonuses, it’s just not that bad. I do find Hibernate necessary to have just in case, but I rarely use it. I would say its mitigation is approximately the same as Shield’s for me, after accounting for the fact that my Shield needs Ageless Core where my Ice can easily go Radial. Ofc Shield wins offensively, but I guess not every set can be that awesome.
I have at least one tanker of every primary now, pretty neat.