Kirise
OG
Blizz has really addressed the issue with twinks getting an advantage other levellers this gem change, the SL rep gear change, it is all pretty even now yet the BG queues are still separated.
I don't see this at all. Even if we're generous to the average leveler and say they have fully enchanted BoAs for quicker leveling, a well-geared twink easily surpasses 10-20% of a leveler's stats. That may not sound like much, but smaller advantages than that keep some twinks from playing when they miss out on grandfathered gear until that gear gets nerfed. More to the point, it's close to the percentage difference between regular twinks and those who exploit the XP-off debuff to get higher-geared twinks into the battlegrounds and obliterate everyone (to be fair, that advantage is more about the additional abilities the exploiters get by being higher level).
PvP templates in Legion (and XP-off segregation) showed us that when twinks don't get significant enough gear advantages (and it doesn't take much), most twinks leave. The gear advantage remains very much alive and well in SL in the 20-29 bracket, and would be even more pronounced in each bracket higher if Blizzard recombined queues.
Plot twist: the gear disparity between players is comparatively even more pronounced at endgame, in part thanks to Blizzard's work of toning down the egregious differences in non-endgame gear like SL rep gear and TBC gems. So yeah, Blizzard might as well combine queues again and let the interest in twinking crescendo. I just feel bad that if Blizzard did, that would once again put F2Ps and vets in an inferior spot. The extra abilities that 29s get in that bracket are just bonkers.