Hi! I'm an Ubuntu MOTU (Master Of The Universe [repository]), and I noticed a packaging error which is easy to fix.

Since libwacom9-surface is essentially a patched version of libwacom9, it needs a "Provides: libwacom9" line in debian/control. Otherwise people who try to install libwacom-surface from your repository (like myself) will have a bunch of packages that get uninstalled since, as far as apt is concerned, nothing meets the libwacom9 package requirement.

I hope that helps!