We were at WL from Aug. 14-23 last year. We didn't think the crowds were bad, but I am not a good judge of crowds.

I don't notice it being better or worse no matter what time of year we go.
I have to say I found transportation from WL MADDENING. Bad enough that I wrote to WDW when we got home.
The bus stop for MK had a "hood" over it, so we were never really sure if a bus to MK was coming. We mostly went by boat, which was fine. The one day we had an 8 AM ADR for Crystal Palace the sign on the dock said boats run from 6:45 AM. Well, no they don't. The boat to the Contemporary runs that early, NOT the boat to MK. We ended up taking the boat and then walking to MK because the monorail would have taken too long. I was FURIOUS. It was so hot and humid that we were all big melted messes by the time we got to breakfast.
The bus service to the other parks was like "bus roulette" - round and round the buses go, where they stop, nobody knows! We stopped at the campgrounds, the water parks, other resorts (Contemporary, GF, whatever) so there was absolutely NO way to plan for travel time. You never knew how many stops a bus would make before you got to the park you were trying to get to. The night we went to La Nouba it took 55 minutes to get to DTD. That was on the bus that we boarded AT WL! Coming back we took the bus to the Contemporary and rode the boat back to WL because no WL buses ever came. The transportation really, really irritated me.