Honestly, my thought process is purely based on taking that rumor seriously that it’s going to be announced on December 10th, so my viewpoint is a little skewed by that. But this promo is obviously meant to drop sometime in the next 6-8 weeks given it’s a preview for 2021 and seems like something that would probably drop during the Christmas Day special (if they have it?) or during one of the Christmas Day NBA games.
That being said, maybe in my mind I just thought the best release date for Black Widow, if it’s released on Disney+ would be New Years Day. Two weeks before WandaVision is plenty of time for people to Rent/Buy/Watch. It also gives them 3 weeks to market the movie, assuming that December 10th announcement date. That’s not much time for theatrical releases, but a home release it’s a good amount of time. Merchandise is already out, or at least most of it is, and it’s been out since March/April.
It was only about 3 weeks between Mulan’s Disney+ announcement and release, iirc and I really hope they don’t think it was that small window being the reason why it didn’t do well because I don’t think that was the case at all and not at all comparable to an interconnected 23rd movie in a franchise.
April just seems awfully conservative with everything that could potentially happen in the next 4.5 months. You’re more likely to catch people unable to go out with potential lockdowns and/or curfews and of course bad weather in early January than you would in April as well. And they’ve got a lot of other MCU/Star Wars content coming out next year that they don’t need to push this back that far, it only further delays some already finished projects like Loki and FatWS.
As far as the promo itself, I can’t say I’m any more thrilled than seeing Enchanted in there.