I'm surprised to say this, but BfA takes top honors for me for the best twink expansion so far. Better than TBC, Wrath, Cata, and MoP. I have a lot of great things to say about those expansions, but they also had some big challenges that I think people forget.
TBC had decent class balance for 29s and 39s, and it's no accident that a lot of old-school players compare BfA to TBC. But back then, the gear disparity between twinks and nontwinks led to more frequent blowout games when twinks did show up.
Wrath laid the foundation for a lot of the community building that influences twinks to this day, including some of the greatest organized efforts ever seen in the 29-59 brackets. But people forget that each bracket struggled with the conflicting aims of casual vs. hardcore twinks, and all four of those brackets eventually collapsed at the end of the expansion as a result.
Cata saw the most egregious burst damage ever put forth in WoW. I played every live bracket from 19s to 80-84 (spent the most time in 70s) and learned a lot from the difficult games. Lailu and Kiendro's qlist app/site saved the midbrackets at the beginning of the expansion, and trolls killed the midbrackets (sometimes multiple times).
MoP slightly (and I do mean only slightly) eased the burst, and some of the conflicting elements of each twink bracket subcommunity finally made some strides to work toward better games. I don't remember much beyond that, other than
@Chops talking me and a couple of mutual friends into giving F2Ps a try. That experience with 20s on Korgath, organized by Kochi, remains one of my best twinking experiences in the game.
To continue in
@Roboartist 's footsteps, BfA feels like the light at the end of a long tunnel. I left in WoD, stopping by in Legion only briefly to do a little Invasion Pre-event gearing, and finding little to keep me. Here in BfA, Blizzard's simple addition of community channels made the single biggest impact on twinking that WoW has ever seen. Decent gearing is easy and BiS gearing is hard for all brackets. Gearing information travels fast both within and between brackets. Some brackets see a big difference between twinks and non-twinks, but nobody dies in a global like in Cata or MoP. Yeah, PuGmades contribute to seriously imbalanced games thanks to Blizzard's ailing matchmaking system, but the aforementioned communication helps factions coordinate a little better.
There's still plenty of room (and low hanging fruit) to make twinking and instanced PvP in general better than what it is now, but BfA is already the best twink expansion I've ever seen, and we're just getting started.
