Back in original MOP we used to be able to queue up arenas in lower levels allowing more options for twinks and simply more fun for casual players and pvp players. I did it myself a lot and it was a blast. The only “downside” was that you were able to cheese achievements like 2.2 rating, 2.5 tabard, arena master etc. But you were not able to get gladiator or r1 afaik.
Including low level arenas into Mop Classic would be super nice to get the most authentic experience in my opinion. The twinking community isnt super big but it serves a lot of extra content and fun outside of endgame content during downtime. Only having BGs available as a twink is just super sad, open world pvp is not an option due to the server balance… unless you wanna make a horde twink on a ally server. That will be hard to do aswell because you will need your main or another 90 character to boost the twink.
Getting a reply from blizzard on this topic is very appreciated!