On AD the Alliance benefit hugely from WM on perks because they are the majority and they aren’t generally sharded with other realms. I’m not exactly sure how much PvP goes on.
I personally avoid RP realms as a non RPer but there are no rules against it ofc. I just feel they are already a minority interest and they only have a few realms available to them. I have a vast choice of realms and I like to be on one of the most populated.
It can be much harder IMO to find a casual home if you haven’t got a goal like raiding, pvp, m plus in mind. I look for a guild based on progress and what they are advertising for and know what resources are available to me. We don’t really have an equivalent for casual or just fun communities other than just scrolling through lots of guild ads.