An OB will give you a little weight, up atop the transom.

An IB would provide a greater mass, and place it well down in the hull.

It would seem to me that the lower COG would be a benefit, but I guess that
would depend whether the actual mounting is below the current effective COG.

I'd think most NA's would consider the weight and mass of an inboard when
designing a boat, so in some cases it might be foolish to actually remove an
existing inboard when making a swtich to OB power.

Diesel is an option with an inboard, not really so with an outboard. Just the
diesel vs. gas equation should make the inboard more reliable than the
outboard.