Honestly, I would love the idea of doing it through a division system. I don't think we'll get more than 12 teams for a tournament like that and even then, 24 regiments signing-up is ambitious (but not impossible given the high reputation of the event and its host). That would make it 6 teams per divisions, a 5 weeks round-robin ​stage that you can either consider sufficient on its own to crow a winner or use it as a seeding tool for a playoff stage that could include 2/4 teams.
Pros:- Everyone gets to play against each other while still facing coalitions of a - somewhat - similar strength.
- The format is adaptable. Less teams than expected -> Shorter round-robin stage but larger playoffs, with RR essentially working as seeding and no longer to eliminate the weaker teams. More teams than expected -> Longer round-robin stage but shorter/inexistent playoffs (just like a regular league).
- Decent schedule. Two months at maximum, regardless of which formats you go for.
- Regardless of the format's choice, most teams will get to experience 75% of the event meaning they actually will enjoy it to its -almost- full extent.
Cons:- I suggested the idea?
Also I feel there is a need to be having this discussion. I didn't play nor ref many matches in the last edition of the 2v2 but from the little I have gathered, I personally found it hard to find a real hype when it came down to many interesting match-ups either due to the way people played but also due to the maps. Kincaid took a lot of time to work-out some proper custom ones and honestly I think it was vastly appreciated even though it's true they were a bit large, but my biggest concern was how bland they were.
When I think about 2v2, the first things that come to my minds are these:
I got none of the vibes these videos give me in the last 2v2s I played or watched. It was a lot of running to get to the enemy and often, a lot of chasing once you got close because the regiments that would deem themselves less skilled in melee would simply abuse the run-away and fire strategy, which although legitimate, makes for a lot of really boring matches. True enough, you can't change the way people play BUT you can impact it in how you approach your custom maps. By making them extremely asymmetrical, without any big hills or complicated terrains, you essentially encourage that bland/charmless gameplay that I feel was simply too present in the last editions.
I really miss this old vibe style, I know not everyone got to experience it but you only have but to watch the videos I linked to understand how cool a 2v2 could be. Despite the fire in charge, despite the chaotic melees, it was so much more straight to the point. In the examples I linked, the IVe knew they were the weaker of the two in melee yet they did not refuse these big engagements, instead they embraced them and tried to make the best of them, which lead to countless close rounds that could have gone either way. In the 91st vs the 92nd one, which to this date still serve as the reference for 2v2 competitive matches, you can clearly some big-ass shooting and out-manoeuvering phases that inevitably always end-up in big melees. The first instance of the rounds never drags on for too excessively long.
Obviously, the fact both lines are around 30v30 in these videos also helps to make it look so much more epic/entertaining. But it also comes down a lot to how you approach such a format and personally, I would very much prefer if we divert from what has been the recent meta where everything has to be clean, even, on either sides, to try and go back to the old style. I am 100% convinced everyone would get to enjoy it more.