In a way, it doesn’t matter if you buff or neff, in either case you will still hit a limit in both cases. By adding more Torment levels, the limit will only be hit at a higher level.
I’d still prefer making everything, as you put it, worse. In theory it should be easier to balance out all the numbers when they are “smaller”.
If you can believe the streamers, one of the main complaints/problems is build diversity, and I do believe that - I personally try to play a Staff of Lam Esen Charged Bolts build every season, and it is a little frustrating, as that build really sucks compared to all the metabuilds - which makes me somewhat unpopular in open groups 
…. If every skill was equally bad, then the monsters would stand a chance and it might be a game of skill? maybe, maybe not