Ctrl+Alt+T should add default text more meaningful than "tempo"
Currently, if you add a tempo text, you get the word "tempo". Why not default to something that actually reflects the current tempo? Eg, (crotchet) = 100. Oh, and just as with Ctrl+T for staff text, Ctrl+K for chord symbols, etc, you should automatically be placed in Edit mode.
FWIW, regarding what to use for the beat value (eg, quarter versus eighth versus dotted quarter, etc) I'd suggest the following heuristic based on the time signature, might be useful elsewhere too:
X/2: use half note
X/4: use quarter note
X/8: use dotted quarter if divisible by 3, eighth otherwise
X/16: use dotted eighth if divisible by 3, sixteenth otherwise
GIT commit: 892c660