CMB and CMD instead of To-Hit and AC: How bad is this idea?

[DungeonmasterCal]

Discussing Pathfinder combat rules with a friend the other day, he asked, "Why not just drop the To-Hit and AC stats and just use CMB and CMD for all of it?" I just said "I don't know. Sounds like a cluster-foxtrot in the making."

But then I got intrigued. Is this a terrible idea, or crazy enough it just might work?

[StreamOfTheSky]

It's a terrible idea.

First of all, armor, nat armor, and shield don't do squat for CMD.

Second of all, the CMD numbers are completely borked and IME by mid levels without HEAVY specialization, it's near impossible to beat a monster's CMD. Good grief, trying to with iterative attacks...
If you want your noncasters to miss a lot more often and physical protection to become meaningless, I suppose this would be the system for you. What's the working title for it? "Casters' Paradise"?

[stringburka]

It requires some reworking of the rules, among other armor as DR and new shield rules. For lower levels, say an E6 game, it sounds interesting.

[Shfish]

Just have the ac items that don't add to CMD become DR...since your armor doesn't prevent you from being physically touched by attacks it would still make sense.

[Jorda75]

Monsters specifically built for grappling and the like would utterly destroy parties that would otherwise be able to handle them, bad bad idea.

[DungeonmasterCal]

Kinda what I thought. The cluster-foxtrot notion was the right one.

[Goth Guru]

Yyyyyyeah, I don't use CMB or CMD because I don't understand them.
I'm going with bad idea.

[CBDunkerson]

Other than a few factors CMB and CMD are 'To-hit' and 'AC' values. I consider them just another variation like 'melee attack bonus', 'ranged attack bonus', 'touch AC', 'flat-footed AC', et cetera. There are lots of specific situations which add or remove a few factors... these two just have different naming conventions in the rules. Which is kinda silly, and why I often call them 'maneuver attack bonus' and 'maneuver AC'.