Being in the process of putting together my own creature book and the recent dragons discussions elsewhere I've started questioning why only three creature sizes? I can see not wanting to have a dozen size classifications but small is really only barely adequate descriptively for things like rabbits or toads or bugs for that matter. Conversely, large is somewhat too generic when dealing with creatures the size of trucks, trains, or small supertankers.
That in mind, I am thinking of changing how I denote the general size categories.
Tiny: insects to 1.5 feet -----------Defensive Bonus +2
Small: 1.5 ft to 4 ft -----------------Defensive Bonus +1
Medium: 4 ft to 7ft -----------------Def Bonus 0
Large: 7 ft to 12 ft ------------------Def Penalty -1
Huge: 12 ft to 30 ft -----------------Def Penalty -2
Gigantic: 30 ft + (unless it's kaiju. Then it is 'zilla!) :)~ --------Def Penalty -3
Thoughts? Counter Arguments? Concurrence? 'zilla?
I agree fully. Didn't 3.5 do this in great detail and add lots of tactical move stuff too. Too much for me, the 3.5 dealing, but I liked that if you were "slower" and small, you at least got +2 to AC.
I have made dwarves per the CKG weight and height Medium with full 30' move with only the shortest dwarf moving at 25 feet. Weight over 90# I called Medium. Thus only halflings and gnomes need to worry about being "small" and possibly moving at 25. I never make any PC move at 20 no matter how small. Rabbits are tiny, try out running one of them! Its a fantasy world, my halflings and gnomes are fast walkers, but I've wanted to give them some BONUS for small rather than the constant hassle of equipment, tall steps, etc. Boots of striding and jumping for all! But I think a simple framework like you have is a great idea.. write up a small article for Domesday.. Please look at what you add with an eye to what I wrote on weight and movement. You might be able to draw from what's there and carry on. I would also love for you to write up magic item bonus against creatures needing +magic to be hit and incorporeal creatures.. that ruling is NOT obvious and deserves a good write up. I think I might do one on duration of buring light sources ..