There's a whole combination of things going on when you compare full wads versus a working (read: expanding) JHP.
First, I lean towards the school of thought that says the temporary stretch cavity isn't that important to wounding (at normal handgun ammo velocities - get past 2,000fps and it's *different*). SOME tissue excepted (liver, kidneys and brain). But when we're talking blood loss effects, it appears that all but the tiniest blood vessels are "stretchy" enough to survive even a close near-miss *most* of the time when the total energy levels are at the 9mm level or below.
That being the case, at least when we're running marginal power levels such as 38+P or 44Spl from a short barrel, a flat-faced full wadcutter will punch deeper than an expanding round, at the expense of expansion. And as an additional benefit, the wadcutter will behave that way even if it hits bone or heavy clothes or some other material that can cause a JHP to fail in a fashion that turns it into "round ball equivelent"...at which point the full wadcutter is now a BETTER wounder.
But, and it's a BIG but, most full wadcutter ammo is loaded too light to make any sort of valid comparison OR trust them for defense. I'd love to see some independent velocity data for the Village Metalworks full-wad-with-a-slot design...if it's a 148 going past 800fps, it should be respectable even if that slot does nothing (and if one petal does break off and it tumbles, now we're in a whole different ballpark - I wouldn't want to be hit by any such thing!).
The other problem: wadcutters don't feed well out of speedloaders if you're in a hurry.
In 38Spl+P, the 158 lead hollowpoints at the 825 - 875fps range from a tight 2" gun (Winchester, Remington) seem to be the best compromise. When they don't actually expand, the edge of the hollowpoint cavity does seem to "spread a bit" to about caliber bore, which means it's now just about identical to a full wad in wounding power yet has good energy behind it compared to a "target wadcutter" (148 @ 700, 750 if you're lucky).