If you are looking to experience all you missed last few years then don't start out on your level 80, start up a new team. They have completely reworked the leveling process so you might want to give the entire 1 to 110 a try. The jury is still out on whether its fun or not.

For me, I started playing WC2 Christmas of 1995 and except for breaks to play Rift its pretty much been Blizzard and only Blizzard for over 20 years. Is WoW fun to me or am I just addicted? Who knows?

As for composistion since its late in the expansion, maybe go the fun route with Warlocks and a Priest. Or all tanks. It didn't take my 2nd team more than a week or two and they are 920 ilvl range, gear is quick.

You could join MiRai and Super in their boxing guild and level up a couple teams with them. I think right now they are preparing teams for the next expansion not enjoying the remaining of this one.
https://www.dual-boxing.com/threads/...Ganis-US-Horde