Although Finale has HP enabled rit. and accel. expressions, we need a way to tailor an accelerando or ritard from a specific tempo to a specific new tempo over selected measures. Given the arcane workings of the MIDI tool, a plug-in could simplify that process by allowing a user to choose a starting tempo, an ending tempo, and perhaps whether the rate of change would be straight or parabolic, etc.
I know there are (crude?) work-arounds, but a dedicated plug-in would make this process vastly simpler.