A 10% strikeout rate for batters is probably somewhat restrictive, but I don't think it means the most expensive team in the world, since it is usually expensive power htiters that strike out more often. And 10% for pitchers is not a high bar, since even if a pitcher pitches all nine innings and gives up ten hits and so face 40 batters more or less, we are looking at 4 K a game.
Why make it 250 million? It seems like more a 60-90 million range league and an interesting idea. Why exclude a lot of potentally interested people who don't want only all-time superstars in the league?