Echoing the masses
Level 43 Deception Assassin right here and I have had no trouble soloing so far. Talos is the perfect companion for any fight, imo; I solo'd a champion level mob yesterday that was a level ahead of me, which is a lot easier if they're melee. This is what I do:
Stuns, stack damage, force slow/speed and kite, stun when CDs are up, rinse and repeat. I prefer Drellik in these types of fights, but any companion could do if you have a personal preference. If you're fighting a ranged elite then do what others are saying: Use jolt, electrocute, overload, (low cut if you're deception) when they're trying to activate skills.
Assassins don't suck, you just have to get out of PvE facerolling mode and pay attention!