Isn't that just taking the talents best suited to the encounter? I mean, if you want to continually keep the talents you like because you like them/the playstyle and aren't fussed about your damage relative to your group's then that's your prerogative, I suppose. As a longtime rogue who never brought anything to the table other than sexy damage (until smoke bomb was introduced), I can't say I've felt the need to keep talents that I especially like if I can do more with another one (unless the difference is very minor or the playstyle too convoluted for my liking).
I'm not in beta, but I don't see, for Assassination at least, one standard talent setup that will just let us ride our way through the expansion. As under-developed as our tree is, I do think we'll be making changes to more than one talent row per encounter. As much as Agonizing Poison takes time to ramp-up, I have read it leads to superior damage over Deadly making it the choice in pure ST encounters (if there are any at all). If you need to cleave/aoe a bit more and the dots will tick a good amount then Blood Sweat will be the go to and, by extension, Hemo. If there's just burst aoe needed then I imagine you would use Deadly for the artifact trait and Master Poisoner to increase your FoK damage.
I am mostly just spit-ballin', though. I have very little interest in Outlaw and am just trying to decide if I want to pick up Assassination or Sub first. It's about a 55/45 split for me in favour of Assassination right now, because I think it will be the most well-rounded in terms of doing good ST while not being total gimp that Sub is in AoE...but, like, phat DfAs sound fun