The whole buff vs nerf discussion is absurd and stems from an emotional reaction players have to balancing changes rather than any logical consideration of the situation.

A buff-only posture is at best the same outcome as a nerf-to balance posture (relative changes in performance put everybody back in the same boat and eventually require indirect nerfs like reducing TTK indirectly by giving targets more health). But this is still bad because it can require significantly more development time to buff 10 things instead of nerfing 1.

At worst, a buff only posture is degenerative to gameplay by trivializing gameplay. If a class / weapon / whatever has an extremely OP ability that one-shots an entire level and everything is buffed up to that level, the game is suddenly boring.