This is definitely a situation without a lot of precedent when it comes to Apple, so there's a lot of speculation going on. I strongly doubt that no one will get their Watch on 4/24, but it might not be the majority, and if Apple spreads deliveries out throughout the dates supplied, I would not be totally surprised. Those of us with dates in mid-May, then, might not see a lot of changes in our estimates.
It's a guessing game until late this week/early next, when shipping emails start to go out and the dates start solidifying. The amount of garment rending and gnashing of teeth in this forum if folks with 4/24-5/8 windows start getting solid dates at the latter end of that estimate will be of Biblical proportions, to be sure. 😉
As for me, I'm just assuming that I won't be getting my Watch until the end of May. Anything else just sets me up for dashed expectations.