No, Soontir is not broken.
This Sunday I was in a small 8-man tournament. 4 Lists where Soontir + Echo or Whisper + another TIE-I, usually Royal Guard.
I faced Soontir lists all 3 of my games and he came down with a big boom every single time.
I flew 2x Red, 2x Bandit, 1x Dagger+Ion+AdvS.
The only list I lost to was the Echo list. Echo took down all of my 5 ships single handedly, after killing off Auto-Soontir and Auto-Royal, simply because I didn't have the PS + he rolled like a beast - but that's dice for you.
The bad thing about Soontir is that he flies as one of the last ships, which means you can often plan where he's going and deny him his actions by making him bump you or fly past you. In my list anyway as I focus on more ships with lower PS.
So, I don't consider Soontir broken but I still consider Echo broken.