If the device is running uEFI, then all the preboot interface support comes from the device manufacturer.
I've never seen the preboot ui be "buggy" though - it either works, or does not work. What problems were you having?
There are are other threads here where people are complaing about the PBA prompt on Windows 8 touch screen tablets and there were no good solutions at the rime: One was marked as answered, but the solution said sometimesit works and sometimes it doesn't work.
We are considering buying the ElitePad, but it sounds like the EEPC PBA would be buggy based on the other threads.
I see now. both those situations were problems with the manufacturer uEFI support. We are stuck with what they offer - if they don't (correctly) implement the pointer protocol then we can't fix or work around it.
UEFI is a mixed blessing unfortunately.