The top three teams before GG- Revan, CLS (Chew, and C3 needed), and Traya
Assuming GG isn't better than any of them, which seems to be popular belief, than investing in the #3 team isn't a bad idea at all
Looking ahead, there's a good chance Darth Malak or Darth Revan (or I guess we can stretch and say malak's apprentice) are coming as a legendary/journey soon, and maybe a HK rework as well.
If you've been on top of your farming for OR round two, you've got a good chance to get this toon on release, who if he doesn't beat revan, should at least make Sith better than rebels again
if not, (and the toon ppl are waiting for still shows), you'll get him round 2, and might as well spend on Traya unless the next big thing is accessible to you
keep in mind the solo toons, and that not every marquee release results in event chars.
that said, I'm one raid away from unlocking traya, and I'll only unlock a ds OR if he is legendary instead of journey, so I'm gonna drop the two zetas on Traya