Max 5 man groups for "normal" queues and separate queue for full premades (different NPCs or smthn?) is an idea that I like, just hope that it's not "too custom" for modern players since blizzlike aids spread so much, ever since 2015 and onwards. Many can't live even with 5g respec, let alone actual custom changes.
On the other hand most players are puggers rather then premaders so this particular change might help out and also attract players to play here instead of being farmed left and right and still have an option to play an actual premade games.
There's definitely something in this idea, it has potential to bring so much good stuff to the server(both PvP and population wise), but it would require some thorough investigation how community feels about it, and simple forum poll that only 100 people read wouldn't really cut it. Bottom line is, we wanna more balanced PvP population and situation, but not at the expense of having 500 players on the server.