I gave up on 300 paragon pretty quickly once I researched the math on how much time it would take. Repeatedly running Pits isn't fun. I finished Season 7 at 279.
I did manage to get a build for each character class to Torment 4, and I did enough pits to get their paragon glyphs to at least L46. My Blood Wave necro was by far my most powerful build, doing 10s-100s of billion damage per cast, with occasional hits into the trillions. In spite of that, I never got higher than pit 140. The build I most enjoyed playing was a Fireball sorc, a great speed farmer who easily deals with most content.
Choosing to get 6 characters to Torment 4 meant that optimizing any of them wasn't happening, and that was a conscious choice I made. I prefer the variety of creating different builds to grinding for incremental improvements for one. One benefit to doing all 6 classes is that I reached 100% on the Codex of Power for the season. I would have expected that to earn an achievement of some sort, but it didn't. I did check off a few achievements for classes that I had not previously used.
Season 8 starts later today. It should be interesting to see how the boss powers function, and I'm looking forward to the reworked boss encounters in general. It looks like Bone Spear necro is at the top of the end game tier list on Maxroll for now, so I will likely start with that and see if I enjoy it. I will likely build another speed farmer as well, maybe a Lighting Spear sorc this time.