We have always gone the first week of June. The weather is good - warm enough to really enjoy pools/water parks (although the pool temps were chilly last year) - but not so hot that you feel like the life is getting sucked out of you. One year when we went, it rained quite a bit. Once, it rained a little. Last year, it did not rain at all. It's Florida - so you just never know.
As far as crowds:
Gay Days - in the past we have simply looked online at the park rotation and avoided the park that looked like it would be crowded on that specific day. Last year, we really wanted to go to the MK on the designated red shirt day, so we tried it. Honestly, the crowd level was not that bad. Also, the Gay Days crowd did not seem to be particularly early risers. The park was really (unusually) quiet in the morning - it was not until 11-12:00 that it started to fill up. We managed to ride every single thing we wanted to ride between the hours of 9 and 12:00. We always go early, and usually can count on about an hour before it starts to fill up - but last year it was quieter longer.
Star Wars Weekend - We've gone in the past , but this was the first year DS was really, really interested in all the Star wars stuff. We planned to get there when the park opened and it was AWFUL traffic wise. The Disney bus driver told us that, because there is only a small entrance to MGM (and no extra entrance for busses) that the traffic to get in in the morning for Star Wars weekends is phenomenal. He said he's seen it back up well past the CBR - and that sometimes they just have to stop charging to park for hundreds of cars so that they move them thru and can clear the road.
This is why we will stay in the BWV on cash the weekend of Star Wars this year. I do not want to sit in the traffic trying to get into the parking lot!
Once we actually got in - the crowds were not horrible. DD was not interested in Star Wars, and she and I had no problem doing non-Star Wars stuff without bad lines. DS chose to basically wait in lines all day for Star Wars autographs - but he was happy as could be and still wears his autographed "Star Wars" hat all the time.
One mistake we made was not realizing how quickly you need to sign up for the special Star Wars activities (like the Padawan Training Academy). Next year, either DH or I will get up extra-early and get there pre-opening to act as a "runner" and sign DS up for the limited participant events.