I do think the substitution rule hurts development-especially at the younger ages. Once you leave the game, (even if its' 10-15 minutes into the game) you're out for good. Here's an example...there was a team playing, had 16 on the roster (coach likes to roster small for a more equal playing time model). In the first half, subbed two people. In the second half, subbed 3. Immediately after the second half started, one player injured her knee-down to 10. later in the game, another kid rolled her ankle. Now down to 9. Nevermind that we had 4 healthy kids on the bench, but couldn't reenter because of the stupid sub rule.
For teams that keep a roster of 18 for games...can you imagine how little playing time (or development in those games) kids get as a result of not being able to reenter games? The sub rule was one of the biggest reasons Hawks, PDA, and 2 of the Texas schools left...
Just for accuracies sake, no Texas clubs left DA this year. Texas is pretty strongly a DA state.