First off coming from someone that heals and occasionally does DPS I think I know exactly what this class needs.
Corruption:
First and foremost many will say operatives are the stronger healing class. It is technically true due to the fact that they never run out of energy, unless they force themselves into doing so. Sorcerers provide excellent utility on a rated scenario or even in a PvE raid. The bubbles they put out protect the team from a lot of incoming damage. Now, it comes at a cost. We're always force deprived since it's very difficult to have an opportunity to out of combat heal since we're usually going to be in combat. What I believe is necessary to fix the tree is having an ability like the gunslinger has. "Cool Head" for example would be a perfect way to help force management issues. Every two minutes we could use it and receive 50% of our force back over 3 seconds. We wouldn't have to use consumption as much to deplete our health to get force back.
Lightning:
This tree doesn't need a fix at all. It's meant to be a turret class just like the commando and sniper.
Madness:
Take "Conspiring Force" from the heal tree and put it in the Madness Tree. In addition to "Conspiring Force" ability to slow targets for 10% during the duration of an Affliction they should also have every time your Affliction crits you receive 5 force back. Force management would improve a bunch since tab dotting a few foes would help ultimately keeping that force up. Insta whirlwind would be very nice to have again since sorcs are extremely squishy and another insta CC wouldn't hurt.
~Itchy'eyes