I would have to say the same thing. I would have only moved her over at 11-12U though, not earlier. I loved that she could play T-ball at 5 in the local rec league and got a lot of instructional time in the slow pitch.
My DD benefited greatly from Slow pitch, In our area there were three choices at 10U after coach pitch; you could go to Girl pitch Fast Pitch or Girl Pitch Slow pitch or a split time between both.
Typicaly the most athletic went to Fast Pitch the others went to slow - No one did both except my daughter.
But what was great, while she was OK at Fastpitch and could hold her own (She was a pitcher and got to play all positions on the field and she hit well).
She was the queen of Slow pitch and was always asked to play up at 12's when she was 9 (All 3 of our 12u teams started asking her to play). So it bult up her confidance greatly and made her comfortable to play with older girls and that comfort level made her play better when she was at fastpitch.
Because of the time it took (A game every night + travel ball on the weekends) we cut back to just fastpitch the second year of 10's -
I would have taken more time to research her first Travel team - But looking back it probably helped her greatly - She learned the basics very well but was on a really bad team for two years. but the good that came out of that is it pushed her to do better. She became a better pitcher because she knew she had to strike girls out because balls on the ground would be an adventure and couldnt walk anyone because the ball would be thrown around and they would score.
We did great due dilagence with her second team went to games, talked to people but eneded up making a mistake anyway - What we saw a coach who cared about his girls and was very good at coaching them was actualy a coach who was very good with "His Girls" and was not concerned about whoever els was on the team there were just a core of girls the rest were filler and the whole team treated her that way - This taught her to perservere ( Part of me wishes we would have left that team so she didnt have to put up with the crap she did - But we were all about filling our comitment - I'm thinking even though it sucked for her she played through and got better so it was probably a good thing)
The next couple of years we were with the same organization with a middeling team and that was OK she liked most of the girls she got a lot of circle time.
Shes with a better team now so we'll see how this year goes.
So Overall - I dont think I would change anything - I wish the road was easier but I think in all, the path has made her a pretty good person and thats really the goal