Guild Wars 2

Since beserker gears are getting nerfed, is it better to just use knight gear for both pve and wvw?

In PvE as much DPS as you can get is the best
Meaning no, Zerker is still the best even if it’s getting nerfed by a bit

Zerk gear are getting nerfed, yes, but your damage is reduced by 10% (more or less), not by 30%. You can inflict the high amount of damage. The difference in pvp is low, just to let the condition damage be more appreciate by players. No more.
Play your berserker and be happy :-)