Input from one person who would qualify and who has long advocated for HBD escalation worlds.
More important than any other point – Good on you for doing something (ANYTHING) to have any kind of premier / escalation world(s). One of the issues that has limited HBD from the start is that we're all being forced to fly in coach, with no chance to perform or pay our way into economy plus, business class, first class, or a private jet.
Having ONE premium world is bad idea. As the comments indicate, there are many different options. Still, please do ONE first. Then another, with a different model. We'll all learn.
I want HBD to make more money, and WIS to invest some of that money back into HBD. I will joyfully pay more for what I consider to be a better product. That includes being in a world others aspire to be in and must pay or perform their way in. Worlds where everyone has paid for at least as many seasons into the future as their longest player contact. WIS issuing a patch release every two months that fixes bugs, adds world-level options, and fixes things that, if there is enough consensus, need fixing. If I pay more, I want more. I'm not motivated to hand you more money if all I get is a star next to my name saying I'm in a premier world.
Neither paying $50 / season or winning $1000 will have any impact on my life. If bigger prizes is what it takes to make premier worlds work, so be it. I'm not against the idea. Just don't care.
We have zero reasons to trust that HBD management, or anyone, knows how to create 32 “evenly matched” teams. Pretty sure that's always been the goal. Many of us have experienced that seeming not to happen. Unless you generate identical teams, there will always be at least 1 out of 32 being unhappy with the evenness of a team they just paid 2X or more for. Some of this is opinion, different people liking to build teams different ways, and therefore not happy with the hand they were dealt. Therefore, I don't see ever wanting to be part of any world with a fixed number of seasons, as the first day at least one or two GMs will revolt. (Clearly you're going to fill the world you've described.) I don't think a promise of creating 32 “evenly matched” is realistic, unless all 32 are identical.
I agree with all comments that a 5 season model will result in a race to cut all budgets but salary. It will be a version of HBD that is almost entirely a FA bidding content. HBD FA Race is a strategy game that can be played different ways and more or less effectively. It will not be all luck. But it's not HBD, as the draft and most IFA will have no impact on 5 season reason results. Unless you bring them all in fully developed. Which then makes coaching even more useless than it is.
Life happen. People's priorities change. You will need to replace GMs. Free team in a “premium” world shouldn't be too hard to fill, until the last 1-2 season if the team is out of it. Who wants that team?
I would be more interested in promotion / relegation worlds if those things happened every seasons. This its own complicated topic.
Good luck. Please try this. Accept many will criticize everything. Don't let the trolls win.