Daddy I appreciate hearing your thoughts on this. I get where you're coming from but this has been a hard and fast rule for over 15 years (if my math is right).
Here is why the rule is he way it is. When you join AOD you are not joining WT/AOD. This is one clan and not a community comprised of many clans. I am not saying you can't go out and play with friends because you can as an AOD member. As you stated this is not a concern because you play 1 game at a time. If or when a new game comes out and you'd rather play with those friends than you are more than welcome to leave AOD and wear their tags. No harm no foul. You can always rejoin AOD at a later date. Hell if you want the best of both worlds talk to those 5 friends and let them know you had a good experience here. See if they'd like to come along for the ride.
Mostly when new games and divisions start people from all divisions move to the next game. Most likely you'll follow friends you make here to new divisions.
In your recruitment this should have been mentioned with you agreeing for membership. If not your recruiter will need a refresher.