Those last two bullets would be huge. I have a personal tailnet and another for my org. Switching between them is just annoying enough that I might even pay for that feature.

I always get so close to just setting up wireguard and being done with it. I barely ever change the devices on my tailnet, anyway.

I do have a couple friends on my tailnet to give access to some stuff, so that might be annoying to migrate. That and Tailscale handling all the other networking stuff I might not even know about like cgnat.