the end difference for the explosion radius change was that the most significant loss of detection/damage was where the corner used to be. If I'm interpreting the numbers right, 2007 tf2 had rockets be map aligned squares w/ 242 as the perimeters, and then changed it to be a radius of 143.
Rockets became 18% bigger when aligned along the map's axes, while the diagonal of the square went from ~171 to 143, so the rockets became ~17,3% smaller along the diagonals.
actual rocket area mildly increased, so assuming they use the same method to do bounding boxes, you would end hitting slightly more shots because of the change than you would lose because of it, assuming that map alignment is random in such a way that you'd end up facing the diagonal and the perpendicular sides relatively consistently. Since most maps flow along the grid, you'll probably see a slight buff to projectiles as the hitbox extends slightly further in the direction most of the combat tends to orient itself around
or im wrong idk