I havent killed General in 10 man, but a few tips from our 25s if you want.
With the mob being untauntable you are very responsible for your own threatcapping, the tank will have a hard time as it is and when he is moving during surge of darkness he is generating no threat.
Our guild doesnt dps as casters until we can get in a shadow crash. This may or may not work on 10 mans based on gruop makeup but other than debuffs and dots we dont burn until in the debuff. This maximizes your dpm, which is way more important than dps on this fight as a caster. Not casting for the first few seconds waiting to get in a crash also gives your tank a head start on threat. We get into a shadowcrash and burn until the crash fades or we have to move, repeat til low on mana, then get into the saronite aura when it comes down. Then wand or dance and laugh at the boss until you can get into another shadow crash debuff.
Also make sure to leave 1-2k mana at all times for counterspells, the boss is currently bugged and sometimes it moves at full speed during surge of darkness, in which case your mellee interrupts wont be able to keep up. You will need to counterspell
the searing wave(? sorry cant remember exact name). For threat dumps invisible after the first or second shadow crash debuff burn and after that the tank should be far enough ahead for the rest of the fight.