Well, April may be too early. There's no point in going if the high trails are still closed. That's some of the best stuff.
The prime Yosemite season is very, very short. Especially nowadays with snowmelt getting less and less with each passing year. You want the waterfalls to be glorious, but you don't want a bunch of the best trails and sights off-limits due to snow.
Frankly, it's all about May.
As in MAYbe we should put Yosemite off till next year, when so many people aren't taking a cruise that takes up half of May.
(of course, next year more than a few of us will be aiming for Japan in April. You can't win.)