There are 3 effective builds: 2handed STR build, handweapon STR build and lightweapon AGI build. Depending on your build you should mainly go for the main traits STR or AGI.
It just depends on what makes more fun to you, since all builds make fun. 2handed has the highest dmg output, can quickly kill mobs but has low defence that can also lead to an quick death. But since recent changes the handweapon build is actually the most effective build for warrior.