I know that the PTR for 2.3 is a lot of fun and there is much to be excited.
T10, once you have spent the same amount of time gearing that you would on live to do T6, is exactly the same.
Greater Rift 45 on season 3 live is, from my experience, equal to something around Greater Rift 58-60 on the PTR.
If the standard for progression has simply been moved 'to the left' by nerfing mobs and buffing monk sets only to accomodate the drawing out of the Torment system, than there is actually no new challenge. It's the developers dragging the X on the graph where 'character development' and 'CPU monster difficulty' meet further to the northeast of the map. The only thing that bothers me is that those who achieve a solo Greater Rift of 55, 60, 65, etc., in 2.3 will seemingly be completing something that, a season ago, would not have been possible if not for the aforementioned changes.