Obliterators are good but it's not a lot of fire support at 2000 points. For a shooty helbrute I think I'd take a twin autocannon and missile launcher. Both guns can target infantry and vehicles. Then again, I think vehicles are the bigger problem so you could specialise it and go missile launcher and twin lascannon/multi melta. If I wanted to keep the CC ability I'd stick with power fist/multi melta. Cheap and a MM shot followed by charge will do some damage to a vehicle
How about meltaguns on the raptors? Two meltas and melta bombs on the unit leader makes them dangerous to vehicle.
If the termies are deepstriking then definitely take the heavy flamer! The autocannon isn't worth the points, you can have the heavy flamer and two power fists for one point less