A number of people commented on the chord progression.
For that, PG Music deserve most of the credit.
From time to time, I like to work my way through various BIAB MIDI-only styles and listen to song demos. I often find that BIAB's demos can provided a good starting place for a chord progression. I was doing that a little while back and came across the style "SwingBal.sty". When I loaded the demo into BIAB for this style, I generated it and it immediately appealed. The chord progression became the starting place for "What Do You Say".
While the original chord progression was in Db major, I transposed it to Eb major, made a few chord adjustments, added an intro, developed a single-chorus arrangement, and the backing was then good to go.
Here is the original chord PG Music progression that I used as the starting place.
Chord progression for Swingbal.sty (SGU)