Best I can tell most pvp issues go back to xrealm battlegrounds.
These were NOT a thing till 1 month left of vanilla and tbc was coming. The 2 years previous were SOLEY against your own server.
So what did this mean?
AV was NEVER used for ranking. It was hours or days of 1 game, rep grinds etc.
What happened on classic? Became solo Q AV grind, alliance premades zergjng etc etc. Thankfully this was changed.
The ranking system in general? If you only pvp’d with and against your own server you knew exactly who was playing how much on each faction, brackets were set accordingly etc. Now we have people on some servers playing 2-3 days a week tops while others play 7 days just to squeak into bracket 1. Massive imbalance between servers in time invested to achieve rank 14. We are all in the same player pool, some people shouldn’t be required to invest 2-3x more time.
If we are going to pvp with all servers(or all pvp servers or whatever) they should be all lumped into 1 giant player pool as essentially as far as pvp is concerned we are all competing with and against eachother as if it were 1 server.
Lastly the premade problem. Premades always existed, however when you only played against your own server there was typically 1 or a few premades then the rest play solo or small groups. Typically if you solo Q into a premade back then you would hit a pug next as the premade had to wait longer to find a game.
Insert cross faction BGs and there’s no built in wait time for 15 opposing faction to Q up to premades (esp alliance) get instant pops all week. This encourages any type of premade even 15 randoms from chat.
I do recognize with how poorly blizzard rolled out servers, allowed transfers etc that current faction ratios on a lot of servers cannot support server only BGs.
I also recognize that it’s 2020 and some type of “premade safety” could be setup so you don’t face constant 10 or 15 man groups from the same server.
Anyways this post was way too long.
TLDR; cross faction BGs from the onset has screwed up classic pvp. Change my mind.