I think the ditch model might be a temporary make-shift until HTC got their priorities sorted out.
Some versions ago, typically in the betas, ditches were a lot harder. You had to nurse your plane under 150mph in most cases, find a really flat spot on the terrain and gently settle it down.
I have no idea if that was more realistic, but seeing many real life accidents/ditch attempts end up in valiant efforts of the pilot with tragic results, I think it was more understandable that way.
In my general feeling, the physical model of how planes react to various forces while ditching, felt a lot more realistic in previous versions of AH2.
Except, some planes were impossible to ditch due to weird bugs - like, even after a plane comes to a complete stop it would start bouncing all over, and the bouncing would amplify and then the plane would blow up. In other cases, contact with the ground almost immediately blew up the plane.
So, my guess is HTC just generally toughened up the "ditch integrity" of planes as a whole, as a simple, temporary fix.