Traditionally attempts to divide a bestiary entry into "class" levels has focused on trying to fit everything that a creature gets in it's bestiary entry into a reasonable number of levels.
What if instead we considered the bestiary entry to be more like an NPC class whereas the end result of the monster "class" who be the PC version. Thus taking say a 5 HD creature and giving it enough abilities to make it equivalent to 5 class levels instead of trying to fit 5 HD and a few other abilities into say 3 levels.
Thoughts?
I like this idea. I homebrewed a class awhile back called the Vampiryst. I also think werecreatures would be cool as a class. In my humble opinion, making class levels, racial hit die, and monster hit die all the same thing is a brilliant idea that needs to be employed someday. I've always wanted to play a bullette, ranging from CR 1 to 20. Anyway, those are my thoughts.
Here is an example of what I am talking about using the Minotaur.
+4 Str, +2 Con, –2 Int, –2 Cha.
Size Medium
Speed 30 ft
Darkvision 60 ft.
+4 Perception
+4 Survival
Gore attack: A minotaur has a gore attack. This attack deals 1d4+ Str bonus in damage.
Natural Cunning: Although minotaurs are not especially intelligent, they possess innate cunning and logical ability. This gives them immunity to maze spells and prevents them from ever getting lost. In addition they are never caught flat footed.
Hit Dice: D10
Role: Most minotaurs can be found at the forefront of battle, where their bulk and strength can be the most useful. Occasionally they will wield ranged weapons that can take advantage of their great strength.
Alignment: Any non–lawful
Starting Wealth: 5d6 x 10 (average 175 gp.). In addition, each character begins play with an outfit worth 10 gp or less.
Languages Common, Giant. Minotaurs with a high intelligence score can choose any of the following languages, abyssal, draconic, goblin, orc, undercommon.
Class Skills
The Minotaur’s class skills are Climb (Str), Craft (Int), Intimidate (Cha), Perception (Wis), Profession (int), Ride (Dex), Stealth (Dex), Swim (Str).
Skill Ranks per Level: 4 + Int modifier.
The Minotaur Racial class
Level BAB Fort Ref Will Special
1st +1 +0 +2 +2 Powerful Charge (Gore), +2 Natural Armour
2nd +2 +0 +3 +3 +3 NA, +2 Con, Intimidating Prowess
3rd +3 +1 +3 +3 +2 Str, Gore 1d6
4th +4 +1 +4 +4 +4 NA, Bonus Combat Feat
5th +5 +1 +4 +4 Large, +2 Str
6th +6/+1 +2 +5 +5 +5 NA, Gore 1d8