I have a feeling this is gonna be the big issue for some people. I personally just leave it at the bottom, but there's something to be said that when you have a standard 16:9 monitor, it doesn't make sense to remove that space from the vertical axis when most content is already too wide for that aspect ratio.
It sounds like the most trivial concern, but this is absolutely the level of configuration that makes one contemplate shell or OS replacement.
I'm planning on staying on windows 10 until they pry it from my cold, dead hands. I already had reservations before, but breaking my muscle memory like that is the last straw. Though I suppose I'll have to eventually update when software starts only working on it.
Some users will moan, maybe less than 0.001% will consider moving to a different OS, and things will just continue as it stands. MS knows they have a captive audience with Windows, so they don't have to care what the users want.
In areas where MS does not have a captive audience they are much more competitive and provide much better value.
I would not rule out the possibility that the team that rewrote the taskbar does not include a single person who wrote the original taskbar and now nobody knows how to get drag and drop to work reliably with all formats.