True - you can add ice @80 cap for the extra defense, but it's not required. You can build 80 fire/light/heuk & you've got 60 masteries left for anything. Ice will give you nice defense bonus; you couldn't really squeeze another weapon in there and be effective with it, so y not ice? Ice at L60 gives you nice increase w/ the passive & the buff (42 phys def for each).
Up to you...if you're at 52 now, you're going to want to tap new skills when they're available so I'd say pass on the ice for now and concentrate on 3 trees until farmed & capped. By that time if it looks like 90 update is going to take longer, then add some ice if you have sp to spare. That's what I'm going to do anyway.
