Well, we're a week away from the merge window close, and here's rc2. Things look fairly normal, but honestly, rc2 is usually too early to tell. People haven't necessarily had time to notice problems yet. Which is just another way of saying "please test harder".
Nothing particularly stands out. Yes, we had some fixes for the new io_ring code for issues that were discussed when merging it. Other than that, worth noting is that the bulk of the patches are for tooling, not the core kernel. In fact, about two thirds of the patch is just for the tools/ subdirectory, most of it due to some late perf tool updates. The people involved promise they're done.
Ignoring the tools thing, the rest is just spread all over, and it's all pretty small. It's _roughly_ evenly split between arch updates, drivers and filesystem code, but that's partially because of the aforementioned io_ring thing (making the filesystem side pop a bit). But there's minor noise elsewhere too. Most of the arch/ code is a late ARC update. But none of it really is all that large or worrisome.
Shortlog appended for a flavor of the details (and you'll see the perf dominance there)