I just started WoW again after 3 month break. I see that combat is pretty much go to spec right now for pvp, but i'm wondering why? For me what i have tested combat, it feels so slow for me, such huge energy starve and so on. Is sub still viable at all? Or even assassination?

sub is viable, combat is better

assass is probably only viable for RLS/RLD or maybe smokebomb cleave (dk/rogue)

Assa can actually do quite alot of burst with double vanish envenoms+vendetta+marked for death and nightstalker. This means 3x guaranteed envenom crits (with pvp set bonus) and 50% more dmg since you envenom from stealth and moar extra dmg since vendetta is on. Add shadow reflection for lulz. Ofc this needs some setting up to do since it wont do much good if enemy has popped defensive cds. Works surprisingly good in 2s with some other burst class or possibly another rogue to keep target stun locked.

If you actually want to get rating up i suggest you go combat tho

Alright, thnx for ur advice guys!