He would have done great things, because arrangers are excellent composition tools. Whether covering existing music, or trying out ideas, they are pretty much built around the presumption that a player wants to create a bass and chordal accompaniment to go with the melody.

I perceive arrangers as the latest step in a chain of evolution that goes back to Bach's time:
Pipe organ with pedal division --> home organ --> electronic spinet organ with "easy play" features --> arranger

As most arrangers lack bass pedals, the "Bass Inversion" function is crucial because it gives the player a way to control the bassline. I'm not terribly well-schooled in Baroque music. But it seems to me that you could think of Figured Bass as the original "fake book" notation Interesting question!