Although "A Midsummer Night's Dream" is apparently his most popular play in terms of how many productions of it there are annually. Most probably wouldn't guess that.
it's the easiest choice to make - you can design your way around a lot of actor levels (ie bad actors) and there is a lot of variety in the roles and only a few have to be played as adults
it also has lots or rolls for females who are usually the overwhelming majority of participants
OTOH, most every other popular shakespeare play requires at least 4-5 heavy hitter actors playing adult roles and is male heavy
one of the main reasons i avoid directing shakespeare (and watching amateur or semipro shakespeare) is the cast is seldom strong enough to really do it right (ie even if you get a good romeo and juliet and tybalt and mercutio, by the time you get to the parents and nurse and friar, et al, you're getting deep in your bench and probably don't have the talent to pull off those roles)