You know, I think some of the same principles apply from the real world here. If I were out looking to BUY a franchise in an existing online league, the following would apply...
1. How established is the league and does the league have GM's/owners with longevity in the league
2. How much history does the league have
3. To what degree has the team I'm considering established a tradition of winning, losing or mediocrity
Now,
contrary to real life thinking, OOTP GM's/owners don't assume any monetary risk, even if they pay to own a team. So you would see many buyers prefer teams that lose or are mediocre, simply for the chance of turning it all around. In real life the established teams with winning traditions would be much more valuable because the monetary risk vs. gain is extremely positive, but I wonder really if there'd be much demand for them in the OOTP online realm, thus the price one would pay likely wouldn't be much.
That said, I would pay more for a new team in a new league with no history, for the chance to build that history myself. If the average cost of a team in that league were $10, I would pay $20.
If the league had a lot of history with an established commissioner and longtime league members, with the average value of teams of $10, I'd pay $15 to for a mediocre team, $20 for a losing team and $10 for a winning team. I personally prefer challenge.
That would be a rough idea of my values of franchises in online leagues.