ok..forgetting ground clearance losses, you are correct...it will slide along the bracket the same exact way. I'm pretty sure that's what you're getting at.
My thought on the topic is...rocks, stumps, etc. dochip, dent, etc... extra protrustions (1/4" brackets hanging down...like a knife almost) are more prone to digging into the obstacle (not talking about ground clearance here, totally different subject) the flatter, and more area it has to lay on that obstacle, the less likely it is for you to get really stuck.
Next...again, land on a rock with your control arm....slide down your CA until it's at your frame bracket...either way...it will hit the frame bracket, and we'll assume you slide over the bracket with any design. Keep in mind we are not competition crawlers....we do back up to reposition and stuff. say you slide over that rock with a bracket hanging down...now, try backing up if you notice you don't have the right line...it's not going to happen. If you don't have a protrusion, it makes it that much easier to back up.
Now you're probabaly going to bring up the ramp behind the bracket idea....still not the same...still a protrusion and still MUCH harder to back up over. Better than no ramp, but there are still better options.
I hope I understand what you're trying to say still, and I hope you understand what i'm saying.
_nicko_