I'm an Ice/Fire hybrid and it works well. I'm still able to out DPS a perfectly geared, hasted, level 160 rogue and have free points to adjust between lure of assassins and energy shield as needed.
Do you use points in lures besides assassins? Do you use both fire and ice lure?
I have all of my points currently in bolt, cloak, incinerate, fire lure, assassins lure -- and there are none left. :/
I have a couple different builds I run depending on if we have another Mage logged in to lure Aggy or not, my most used build unless I'm needed for Lure of Assassins is:
50/35 Firebolt (Royal and Minor rings and Aggy bracer)
44/35 Ice Shards (Royal and Grand rings)
30/35 Lure of Fire
30/35 Lure of Ice
29/35 Energy Shield (Aggy Bracer)
When I am on lure duty I use:
50/35 Firebolt (Royal and Minor rings and Aggy bracer)
35/35 Ice Shards
30/35 Lure of Fire
30/35 Lure of Ice
40/35 Lure of Assassins (Godly and Royal rings)
Your build looks just fine though, cloak is a nice add-on to DPS for the tank and incinerate is very close to the DPS of ice shards. Only thing missing is the added ice damage from lure of ice but if your clan members utilize mostly fire lux and earthstone then it's probably not a huge increase in DPS for them.