WTF BRP #1 The SIZ characteristic

So, what is up with the SIZ characteristic? It seems more useless than CHA supposedly was in D&D, but seems to have escaped scrutiny.

Let's take a deep dive.

History of SIZ

Stormbringer upped the ante by adding a Body Type to it, but this was quickly scrapped in Elric! and (so far as I know) never appeared in other Chaosium products. SIZ in Stormbringer is used to determine if there is a damage bonus, but also adds to Hit Points for larger monsters or beasts. It also limits armor one can wear to within a few points of SIZ.

Nephilim dropped the SIZ statistic altogether.

The Big Gold Book (2010), which came out as the official word on the system, has only three pages on SIZ.

Page 26 tells us some interesting uses - it can be used to resist shoving, increased or decreased temporarily via lifestyle, or permanently via damage. 

Page 277 has a list of SIZ of common objects, and notes that SIZ equals Hit Points for things.

Page 296 just has a long list of SIZ and body weight for creatures, and notes that this is not useful for amorphous or gaseous creatures.

Another Use For SIZ

I've always wondered if there might not be another use for SIZ that could enhance gameplay. Specifically, could SIZ be used comparatively to increase or decrease the chance of spotting or hitting a creature or character? The old Palladium Fantasy Roleplaying Game (a true banger despite the mechanical oddities of the underlying system) allowed smaller creatures a bonus when hitting larger ones.

Why not do the same here?

So, what if we say for every multiple of an attacker or searcher's SIZ that the target has, the attacker / searcher gets +5% to hit or see the larger target? We would have something like this:

        Multiple of Attacker's SIZ                                Skill Bonus to See or Hit

                        x2                                                                +5%

                        x3                                                                +10%

                        x4                                                                +15%

And so on. So, whether we have an ogre hiding behind a tree or someone trying to hit Cthulhu, they obvious should have an easier time of it. There are some caveats - this bonus does not apply when the target is moving at speed (ie a dragon in flight) or using some means of concealment (camouflage or magic). Also, this bonus does NOT increase chance of a critical hit. If you have 40% but get a 10% bonus to hit something large, you still only critical on 01-04.

Conversely, we can also impose a penalty to see or attack something smaller than oneself.

      Factor of Attacker's SIZ                                Skill Penalty to See or Hit

                        1/2                                                                -5%

                        1/3                                                                -10%

                        1/4                                                                -15%

And so on. This makes the game more tactical and realistic, while also giving a bit more weight to statistics than the original rules allow.

References

Durall, J. et al. (2010). Basic Roleplaying: The Chaosium roleplaying system. Chaosium.