As there is no doubt that BEAST is currently best place to gather data, we can't forget that BEAST is also only thing that bring all the clans together to engage into competetive scene in Early Acces stage of Bannerlord. Everyone is investing their free time to play the game, and everyone wants it to become better at every aspect. BUT also everyone wants to have fun, and thats why we are all here. Competetive scene at niche game like this is both meant for tryharding and having fun, cuz there is little to none cash prizes involved. If we take away the "fun" part, people will simply quit, cuz there is no money to keep them invested to play thing that they don't enjoy. We can't simply let BEAST be a limitless hell of archer/cav spam. As Bard pointed there are already events planned to let people enjoy the limitless hell, but most of people don't want to/don't have time to sacrifice 8 weeks of a tournament that they won't enjoy.But Beast is also the best event for testing.
We have established divisions and skill levels.
We can, after 3 season, predict how some match -ups play out within the class restrictions rules and compare it to matches without the class restrictions.
We are afaik the biggest team based event in Bannerlord. With the exception of Captain's League maybe (which is a great event!)
Beast is probably the best way to collect loads of data on competetiv play quickly.
Keeping all that in mind, I agree with @Loyal2Odin that bigger limit should be imposed, such as keeping the current one + making at least 3 inf a muss. So 3 cav 3 inf won't be allowed, but 3:2:1 or any other variation wiht more than 3 infs will be. Thus I suggest that class limit vote should get new option with that limit. Let people decide.