I received my Daptor d9 adapters and the paddle support for them, that Kitrinx added to this core, is really impressive. It works very smoothly and even supports four paddles (tried it with Video Olympics that we used to play when I was a kid).
I hope the other cores, like the Commodore ones, can get support added as well. I should make some request tickets. I'd love to play VIC-20 Omega Race using a paddle on the MiSTer. The C64 core has paddle options, but those don't seem to be compatible.
It already works with some of the arcade cores that support analog input. Often selecting 'paddle' as the input type doesn't work though, as that expects a MiSTer Spinner protocol. This might be confusing for newcomers. I also think the Daptor is a more elegant solution, as you don't have to modify your original paddle controllers for it.