The problem with combining MP and TP in order to give Spire a valid use, is that it then makes Ewer and Spire too valuable to Royal Road.
Having Spire as a throwaway card for Royal Road is incredibly useful.

The only card I never like getting is the Bole.
A healer can't rely on RNG for it's healing or mitigation, as such you will always plan your moves without taking Bole into account and when you do get it it's not needed.
Then again, like Spire, I occasionally Royal Road it when I've already got a Balance held, but it's far less useful than Spire.