I'm sorry, but that isn't a ritard at all. In a ballad (for example), suddenly cutting the tempo by 50% just sounds silly. Cutting by 20% in one bar, another 20% in the next, another 20% in the next, etc, makes for a very long ritard--and it still hasn't abrupt shifts in it that don't give the feel of a rhythm section slowing to a close. You might get away with it in an up-tempo piece with a long series of small-step changes, but that's almost never what a band actually does.

What we need is in lots of DAWs: you select a section, specify starting and ending tempos, and in many cases choose a flat or upward- or downward-inflected curve for the change. Nothing else will produce that live feel.