In reply to Nick.

I've developed my own control for border-radius and will be repurposing it to also handle margin/padding. I'll also be developing a control for border styles beginning next week. At the moment I use these controls in plugins only but I'll be rolling them out to my themes too, hopefully soon.

Here's a preview of the border-radius control: https://twitter.com/dgwyer/status/1266700992957034497