Imo, hammers are fine, when they work. I don't main a Titan but recently got Twilight Garrison so I've been playing rumble a lot as a Titan. I can kill lots a people with hammers, but when they don't work I just sit there and get sprayed down while my hammers tickle my enemies. A good way to buff Sunbreaker imo is to just fix the blast radius glitch and make the blast a bit bigger. Also a Bladedancer buff/fix would be nice too.