What if we just make the bite primary?
Slams can be primary or secondary either way. Also, can someone link where in the SRD it says how much Str to add to which kind of natural weapon? I'm not finding it at the moment.
Full Attack
This line shows all the physical attacks the creature makes when it uses a full-round action to make a full attack. It gives the number of attacks along with the weapon, attack bonus, and form of attack (melee or ranged). The first entry is for the creature’s primary weapon, with an attack bonus including modifications for size and Strength (for melee attacks) or Dexterity (for ranged attacks). A creature with the Weapon Finesse feat can use its Dexterity modifier on melee attacks. The remaining weapons are secondary, and attacks with them are made with a -5 penalty to the attack roll, no matter how many there are. Creatures with the Multiattack feat take only a -2 penalty on secondary attacks. The damage that each attack deals is noted parenthetically. Damage from an attack is always at least 1 point, even if a subtraction from a die roll reduces the result to 0 or lower.
A creature’s primary attack damage includes its full Strength modifier (1½ times its Strength bonus if the attack is with the creature’s sole natural weapon) and is given first. Secondary attacks add only ½ the creature’s Strength bonus and are given second in the parentheses.
Well, I think you went from adding +Str to +Str-and-a-half when you went from half-dead to mostly-dead. Let's be consistent.
As for the rest, I could have sworn there was a sort-of standard. I guess I'm just getting confused with Pathfinder, which does have "standard" rules for natural attack Str bonuses.
Also, if the rest of you don't like the single actions at "mostly dead" and cannot run at half dead, we could just do cannot run at mostly dead. That would fit with dragging themselves along with an arm.
Well I went from 1 to 1.5 Str because it was consistent with the 3E rules for creatures with a single attack, but I don't mind changing it if t'others have no objection.
Powerful bite sounds like a good idea, and I agree that it shouldn't get an expanded crit range.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.