Did previous editions have a similiar 'identity crisis'?
I would say no, 2E has a dissimilar identity crisis, in that it took a "Let a thousand flowers bloom" approach to settings, and thus put them out in a pretty scattershot way, but this approach did land them some direct hits (notably the first Dark Sun and Planescape, but also things like Ravenloft 2E and Birthright), for the relatively small sales of the era. Tonally, they weren't as scattered as they might be - all generally had a slightly "teen and up" tone, whereas D&D, which was still being made, was aimed more at younger kids (rather ineffectually, admittedly).
3E didn't have an identity crisis apart from in it's clumsy, failed, attempts to "bring back Greyhawk" (which nowhere near enough people wanted to actually happen). Otherwise tonally and in terms of output they were pretty together, and it continued to be very much "teen and up".
4E created a weird crisis for itself by doing the reverse of having an identity crisis, and picking a very specific identity with new lore for the entire D&D universe, which never quite worked out but gave us a lot of great stuff (not least the Shadowfell and Feywild). Tonally it was probably more together than any other edition. Again teen and up.
5E started out as an "apology edition" and was initially taking a "Let a small and safe number of flowers bloom exactly once" approach with a slow, steady release cadence and zero support for settings beyond the main book or mostly Forgotten Realms-ish adventures. The inevitable WotC attempt to bring back Greyhawk inevitably completely failed (guys, no-one cares about Greyhawk! Sorry to the three people who do!). Tonally it was barely different until it started getting bigger, and since then we've seen the shift towards increasingly child-friendly content.
You think the 5e designers wanted Strixhaven to come out the way it did? Disturbing thought.
I don't think this decision was made at the level of the designers.
I think this decision was made at the corporate level. I think WotC had deluded themselves into thinking that, if they made Strixhaven child-friendly and soft enough, it'd do amazing and bring in a ton of Harry Potter-ish players and so on. Because that's what HP fans are looking for, right, a soft, comfortable setting where nothing bad happens? That sure describes Harry Potter's horror show of a life...
But the resultant settingventure was a bit of a nothing. All the cool ideas got given up on, and it was neither HP enough to attract that crowd (who are, in fact, mostly in their 20s and older at this point - some are about 40, not kids), not much like the MtG setting.
Also WotC clearly lost confidence in it if they ever had any, because it wasn't aggressively advertised, and it really should have been. I know a bunch of HP fans who play D&D, and not a bloody one of them had heard of Strixhaven from anyone but me.