- Being 1" high is like super-duper stealth. Technically you're at -6 to be seen but realistically if you are 1" high and people are not specifically trying to keep you out, you can penetrate any even semi-normal defense. We estimate that is 4 APs worth of value.
- The -6 to be hit is reduced to -3 by many opponents (any L3 opponent who is at range with their weapon). If you are not highly mobile (4y/s or higher, meaning you must have some special movement form) then you do not get your negative to be hit in HTH combat. I counted it as -4.
- The intermediate sizes are somewhat stealthier but far less so (a 10lb small dog is pretty stealthy but not as absolutely dangerous as a 1" high person). I more or less counted their negatives as about half of what they were worth.
- The sold-back Damage Points count against the final AP cost.
- I assumed that most characters would not bear the full brunt of their Size limitations. Small characters would have special movement forms in most cases, characters with no Reach would gravitate towards ranged attacks, and most of the characters would combine a high AGI with their negative To-Be-Hit modifiers to enhance them. I don't assume this is absolute but my experience in other systems (and earlier versions of JAGS seems to bear it out).
Negatives To Be Hit
Negatives to be hit, as noted before, are actually worth a % of your Total AP. We are resigned to using that sort of calculation in a few places (Fast Company, Quick, etc.) but mostly we want to simply use your Damage Level (Very Low Damage, Low Damage, or Normal) as a proxy. We've done that here.
The smallest size (1") actually costs 12 AP if you do Normal Damage despite giving you no Reach, -8 DP, and makes you move very slowly. The reason for this is that you are likely to be at -3 or -6 to be hit and when I ran that character against peers--even with the reduced DP--they wound up winning like 75%+ of the time if they did Normal Damage.
It costs 4 AP if you do Low Damage (that character came out at 50%) and gets you 4 AP (cost -4) if you do Very Low Damage.
The Other Levels of Smaller
These were not all that exciting: mostly they're pretty cheap and/or don't get you many points. The next smallest size (-4 to be hit, -1 vs. L3 characters) would probably be a good deal at 64 AP or higher since the reduced DP wouldn't make up for the negatives to be hit--however, I'm not too worried: there are plenty of things that can still hit you and most, again, peer-battles will involve the reduced -1.
One Remaining Problem
There's a remaining problem with Smaller Sizes: STR negatives. I didn't want to give small characters a negative, fractional, A-Cost (the value of their Attack Powers) for HTH damage. It seems incredibly complex and the fractions would be ... well ... fractional. I'm probably going to have fractional A-Costs in the game--but I want to see if I can minimize it ... and selling back a pt of STR goes against that.
What this means is that if you create a small character who then buys STR you are buying it out of a 1 to 3pt hole (the 1" character has -3 STR). I'm not sure how I feel about that. I'm considering a rule that if you purchase any extra STR through AP powers you can choose to reclaim the negatives for Size.
I don't want to encourage super-strong, very small characters ... but I don't want to hurt them when it comes to HTH attacks either: their loss of Reach and movement already do a lot of that naturally.
A Final Note
Bugs don't have 2 DP and they don't have 7 STRs. I think there will be a Designer's Note that says that if you want to play a real insect--that is really that fragile you can choose to have something like .25 DP and a STR of -5 or something: no matter how well a cockroach slugs you, it isn't going to hurt.
I remember looking up rats in Pathfinder and discovering that on their best-possible roll they couldn't do a point of damage to a PC. I wouldn't relegate a rat to that--they have bio-weapons--but I do think that there is a physical condition where the target is so fragile that the combat system won't properly represent it. The question of course is why would you want to play at that scale ("Hey, guys, let's play A Bug's Life!")--and if you did, would you really need to handle large people stepping on you with complex rules?