I think a second team would be the best route. Even if you're not excited about it. It will fill the void. Do experiments. Recruit lower level players and see how good you can do with it. Try anything at all. Find a world that overlaps the down time of your favorite world, based off the dates.
As far as renewing, I really don't understand how this becomes a problem for ANY coach that is involved in this game long term. A D1 coach has likely put in 10 seasons at minimum. A year's time. So in a game that you check daily at the least, why would someone not leave on auto renew? Or if you pay season by season, why not have 2 credits on reserve at the least? It would give you an entire season to say "oh ****, forgot to renew". Whatever it takes. A coach puts so much effort into creating a dynasty, why not insure it?
Personally, i'm on the far end of this conversation. I have 5 teams, so I order 10 packs. And I never have less than 20 season credits. After tournaments, i wait until i get $100 in credits and i buy the next 10 pack immediately. I just don't really see the reason to wait until the last second, unless you buy seasons 1 at a time, and have only 1 team. But even then, if you care about your program, create yourself a safety net. And if you want to drop the team, you'll surely remember to do that. I doubt many people buy additional seasons on accident. "Oops I just bought another 5 pack" doesn't happen.