Well the thing about nerfing jobs is that it makes everyone feel bad unless they are super absurdly broken, which no job honestly currently is. It isn't so much that melees are too good, because if they were then P8s wouldn't have needed nerfing, it's that non-melees are really bad right now. If you only buff, sure that introduces power creep for older content and can invalidate it, but this game is all about current and new content. So they can buff the bad jobs and the new fights released in future patches will be tuned for those buffs in mind. It's the most sensible solution, IMO. Nerfing is necessary for extreme outliers (like old SMN) but I don't think any job is at that level right now.