Only a attack per round and monsters

[Yora]

I want to run my next Pathfinder game with somewhat simplefied rules (no 5-foot-step, Pin as a combat maneuver to replace Grapple, Combat Maneuvers as standard action) and I want to reduce the number of attacks per round to just one. Since is pseudo-E6-ish, PCs wouldn't get a second attack per round anyway (though TWF and Rapid Shot are still possible), but I'm not quite sure what to do about monsters with multiple natural attacks.

An adult black dragon has one bite, two claws, two wings, and a tail attack, and just reducing it to only a single bite attack would be a significant reduction.

I am thinking that one solution might be to let them make an attack with each type of natural weapon, regardless of how many they have. In case of that dragon one bite, one claw, one wing, and one tail attack.

A leopard would get a bite as a standard attack, a bite and one claw attack as a full attack, and one bite and two claw attacks as a pounce-rake.

Any thoghts on how well this might work?

[Person_Man]

Burst attack. Monster rolls 1 attack roll. Compares it to AC of all enemies within their reach (or a certain number of enemies, if you want to make it weaker). If you want the possibility of "multiple hits" against the same enemy, then use higher value damage dice (which creates greater variance in the damage roll) and/or higher crit threat range and/or multiplier. For example:

Natural Attacks, burst 20 feet, +16 to hit, 2d20 damage (15-20 * 3).

[JusticeZero]

Keep the multiple attacks, but only roll once to hit with the array. Might make damage a bit bursty, but such is the danger of granularization.

[Grod_The_Giant]

Keep the multiple attacks, but only roll once to hit with the array. Might make damage a bit bursty, but such is the danger of granularization.
Roll one attack, and for every X points (2? 5?) over the target's AC, you deal damage as if you'd hit with an extra attack?

Alternately, just roll all of them. Most monsters that aren't dragons have a reasonable number of attacks, and I think it's sort of assumed in their CR.

(Also, a side question: are you doing anything to buff PC damage to compensate for lost iteratives?)

[JusticeZero]

Roll one attack, and for every X points (2? 5?) over the target's AC, you deal damage as if you'd hit with an extra attack?Basically, yes.

[Ketiara]

Are you planning to compensate the melee's for the loss of damage compared to casters? Or have I misunderstood the op?

[Roguenewb]

mundanez are lamez they do so damage ubercharge my wizzo dont get be god in every fiught

In reality. If the level is low enough that iteratives wouldn't have existed anyway, then you're okay. Plus it makes rapid shot and flurry far more special as means to get extra attacks. I think the idea of raises is a good one. Either roll one attack, and then bite if they hit exactly, bite + 1 claw if they beat by 4 and so on. Alternatively, give them a straight attack or (OR, not AND) damage modifier for all natural attacks the creature is foregoing by lumping them together. They only get this bonus on a FULL ATTACK ACTION. Otherwise moving dragons full attacking is gonna shred your players.