I've been in these discussions for like 8 years, and I don't think any new convincing arguments have ever been made. The system is really backwards in a lot of ways, but the bottom line is that the baseline price point is just too high for a pay-as-you-go, online subscription game. So they need the big credit incentives if they want to retain users - but then that leads to the problems we all see with longtime users amassing more credits than they could ever spend on the game, and nothing else worthwhile to spend it on.
I don't know if there's any real problem to players playing "for free" as long as they've already put in up-front investment; and for the most part, players do that when they get to the point where they're cruising. So I think probably the thing I'd do is just turn the model into more of a one-time purchase thing (per world) that you just keep. Maybe $30 per world, or something. You don't get fired, until you get to the power conference level. Maybe some incentives for Final 4 or better, like a few dollars off another HD world or other WIS games, but free seasons wouldn't be a thing anymore, because it would be one-time and done. I think ultimately that also might allow for more growth too, because the price point per season is really high (with no credits) compared to other games, and is likely keeping folks away, especially folks who don't pick up the game quickly.