There's the rub. I've seen parents blame losses on lack of depth on the bench then turn around and threaten to leave if their player doesn't get their "deserved" playing time.
Personally, at U15 and above, I prefer smaller rosters - 15 max. More playing time, the team is better synched, the off the bench players have immediate and planned impact. It's a risk but provides the stronger, younger players to play up if/when their is a gap on the bench. Team culture is more stable and predictable with a smaller roster.
Now, with that said, smaller rosters = less $$$.