It does make it more complicated. 50,000 members (as a round number) suddenly breaking into new groups of those who have paid partial memberships only getting access to part of the season, which part, which games, do they choose, can they pay the rest and get full access again - systems like this don't get build well quickly.
And it could all be kept simple by waiting until we have some clarity on what is actually happening this year.
It's not as complicated as you are suggesting (there are already 100s of payment groups set up) but it is more effort than doing nothing and continuing to take the money you are right on that. Again, I am just coming from what I think is the right thing to do by your customer base but I admit they don't need to do anything because 90% of members will happily stump up the money.