J.B.
If he enjoys the activities, and you don't feel spread too thin, then I don't see a problem with it. I have a 4 year old a lot like what you describe, and we did have lots of playdates, etc. to keep him busy before he started full day prek and aftercare in August, or I would have had to sign him up for some things as well. As it is, I still find myself "running" him -taking him out to literally run, swim, bike, etc. after full days of activity to wear off extra energy! I think problems come in when the child is older and has school, homework AND a ton of scheduled activities causing them to never have any downtime or relaxation and not allowing them time to get adequate sleep, etc. Parents also get in a mess then because they're running all over the place shuttling the kids and watching games, plays, performances, and whatnot constantly instead of once in awhile. Just be careful when he's older not to overschedule him then!