They'll definitely announce Cataclysm Classic, which is fine, the expansion is better than its reputation except for 4.1 (the troll raid rehash) and the abysmal 4.3 with Dragonsoul and LFR. They kept LFG out of Classic so I am hopeful they'll do the same with LFR as LFR is way way worse.
The polls suggested they're wanting to do some things different with Cata Classic, which is great and shows commitment. I mean they're more committed to Classic with HC and Cataclysm than they are to retail with going the same old route again and again for yet another expansion that's been abandoned by most players months ago - MAUs don't lie and Blizzard's silence regarding WoW's performance is defeaning.
It's also time for the announcement of the next retail expansion, but that would be conflicting with their schedule and the possibility of a 10.3. We've been in the same situation with Shadowlands and we know how that went, they just abandoned one major patch. But honestly, it might be the best for Dragonflight as this expansion did a lot of things right, but was ultimately a snooze fest with a very unexciting story and setting. Doubt it'll be a revamp though, people really should get that out of their minds. Simply not worth the effort.
Between an expansion launch in Q3/4 next year, I have a hard time imagining how they squeeze two content patches in just a mere year. 10.2 comes the soonest in October, even if that runs for just 4-5 months overall, there's only 7-8 months left for the final patch of the expansion which would be exceptionally short. If they cut 10.3, they could again have an August launch for the next expansion as it would fit the schedule nicely (10.2 in Oct/Nov, runs for ~ 7-8 months, maybe a small 10.2.5 to bridge the gap, pre-patch in late July / early August, expansion end of August).
By the time of the Blizzcon the merger should have eventually closed, maybe they have something planned for that as well (even if it might be less WoW and more convenience stuff for their products aka Gamepass etc).