I agree with a lot what both sides are saying in this discussion. A Player should not be forced into playing a version they do not want to play. That does not make anyone happy. At the same time we want to welcome new Players and OOB is the standard outside of this website.
For 2021 my suggestion would be to have separate Leagues or at least separate Playoffs. If you qualify for the Playoffs (8+ games) you can play in as many of the Playoff versions as you like. That way everyone gets to play the version they want to play, and no one has to play in a version they do not want to play in. If a version doesn’t get enough interest for a Playoff, then that Playoff version is canceled.
While P2V is a completely different game if there was enough call for a playoffs I see no reason to not include it unless there is a conviction that any Playoffs should only include Global 1940 (OOB or BM3) as P2V is frankly a completely different game; like Big World. In fact, you could have a Big World playoff too if enough people were interested in it. And how about AA50!!! That is one game I would play in League. But I digress.
As a new League Player here is my recent experience. I was playing in my Face to Face gaming group and we ONLY played OOB; well AA50 too, and D-Day and Guadalcanal. You get the picture. We had heard of this Balanced Mod thing but none of us played it. Due to COVID-19 we had to stop playing and I wanted to continue gaming and while I had for years used this site for information sources I had never played here. So, after doing some investigation, I was very pleased to read the League Rules and saw that Global G40 2nd Edition (aka OOB) was the default and based on that I joined and began playing.
I have had no problem finding OOB competitors so far. I can find people to play with at the E, 1 and 2 levels all the time. However, it came to my attention that a majority of the very top M players seem to not only play BM3 exclusively but avoided OOB like the plague, so I have not played against them. While I was disappointed in that it is fine if they feel that way and do not want to play OOB. But, to say if you want to play in the playoffs in the A Tier that you must play BM3 because they do is not fair. Just as it is unfair for them to have to play OOB when they do not want to and have not played a single game all year of it. Thus, why I suggest separate Playoffs.
We are going to lose newcomers if they are forced to play BM3. For those of you who are adamant about how great BM3 is and how OOB sucks, I know just as many people who feel the same about OOB being the best game and BM3 sucks; actually more. I would not have joined the League if BM3 was my only choice. At the same time, I do not want people who only play BM3 to not play in a Playoffs or be forced to play OOB if they do not ant to. Again at least two Playoffs for 2021 would be my recommendation.