Well he have to consider what G0-T0 can feasibly throw at Malachor V:
Not entirely sure destroying the bar, would be that big in the grand scheme of things. It'll get rid of some members that G0-T0 has, but comparing what he has its more of a minor thing. The problem here, is finding G0-T0....though that is only a problem due to the fact he can cloak his ship, the gravity generators will keep him from jumping to lightspeed however so the Sith fleet could search the surrounding area for the ship.
- HK-50 assassin droids
- Gand bounty hunters
- Ubese Assassins
If Traya eliminates all of these, I believe G0-T0 will make a personal apperance. G0-T0 doesn't seem to be adverse to getting his hands dirty, he agreed to travel with Surik across multiple planets and battlefields and personally prevented the remote from reactivating the MSG rather than sending some lackeys to do it.
Now several debaters have said that even without these G0-T0 still has his so called 'Droid Army' - but lets face it, this is made up of a smattering of protocol, labor and astromech droids scattered across the galaxy. Hardly a capable invasion force to penetrate the most dangerous planet in the galaxy. And then we have these. Granted they have the capabilities of reactivating the MSG generator but not without support of the above - there not exactly ground breakingly powerful.
EDIT: The problem with your scenario is that even if Traya traps G0-T0 on Nar Shaddaa, she has to sift through countless freighters and ships that may very well become hostile (see the First Battle of Onderon) and in that time G0-T0 could escape on a private shuttle or an escape pod which he'd likely have prepared.