Heya, Soutarou is indeed taller in this sprite. He was very small in the original due to him being more of a shota type character, and while we didn't keep that characteristic in Revisited, he ended up looking fairly small due to how the sprites were rendered onscreen. With the new sprites, we're making everyone take more real estate on the screen, as well have decided to represent Soutarou being aged up by making him look his actual age, and so the difference might seem a bit stark compared to the other unfinished sprites.
-Devilizer