I do pvp on Alliance side and asked around and apparently there is no pre made team around, so my experience so far was that alliance side is more unorganized than the horde, especially in Warsong Gulch. 10 years ago when i was pvping on Blizz server all the high ranks, me included, were rallying friends to join the effort, both horde and aliiance side did that and we had amazing matches with many pre made teams nonstop. On Kronos it seems there are only 2 full games at max, even in bonus and aaalways against the same well oiled horde premade machinery.
I've been only pvping for the last month on Krones, but like Pipfugl said it remains to be seen how many people are playing in fall/winter times. The vanilla system only worked when the whole server was interested in pvp not only 10% of the active players.
If you make the ptr pvp a regular thing it would draw many people in, no gear barrier, jump in and play normalized pvp matches. Like a wow pvp arcade realm, where you just do pvp with your dream gear, like you had 10 years ago on live servers when you fought for the ranks or even Rank 14.
A vanilla pvp realm with normalized gear would be friggen amazing tbh. No grind just good old fashioned pvp. You could make a league with ranks and give player benefits on live servers for their efforts.