In my case, the bees do bring in honey in the fall, whether or not they bring in more or less, I don't know. I don't generally harvest in the fall because I would rather not feed. I harvest in June and leave the rest for the bees for summer (they will sometimes use all remaining honey in summer) and winter.
The only problem with requeening I have found is that sometimes it fails and I get a deadout. Happens to one or two hives per summer. Other than that, things seem to go fine. My dearth is often months long, June to September even. It gives the new queen plenty of time to get her affairs in order.
They definitely do bring in more stores for winter. The honey is typically much darker. Last year, they brought in very little because very little was available so I had to feed. This year is much better, after early June harvest, performers are currently sitting on a full deep of honey or better. In fall, I'll redistribute as necessary. Also trying to overwinter some nucs. They haven't absconded yet, but they're generally sitting on one frame or less of honey at this point. They have definitely curtailed brooding at this point. There are three.