One of the issues with FF7 is that elemental and status vulnerabilities aren't used regularly or consistently, nor are enemies powerful enough for them to be significant. This is a stark contrast to the bestiary of, say, Final Fantasy X, where monster individualization was really well-emphasized. And this is something I want REBIRTH to address.
How so? The simplest method is to use an unofficial enemy class system. These classes might be differentiated as follows:
HUMANS - self explanatory
ROBOTS - androids, automated machinery
PLANTS - plant-monsters, fungal monsters, etc.
INSECTS - bug-like and spiderkin creatures
FLYING - winged beasts
WYRMS - serpents, scaly reptiles, dragons
ABOMINATIONS - things from Hojo's fridge
BEASTS - mamallian creatures
Enemies will take one or two classes, and may take elemental vulnerabilities as follows:
HUMANS - POISON, HOLY
ROBOTS - THUNDER, WATER
PLANTS - FIRE, EARTH
INSECTS - FIRE, WIND
FLYING - WIND, BOLT
WYRMS - ICE, WATER
ABOMINATIONS - HOLY, EARTH
BEASTS - POISON, ICE
The idea is that emental statuses will be simple, memorable and intuitive. As such, if an intuitive elemental defence or vulnerability goes at odds with the official class characterization, the 'commonsense' element classification 'wins'. The above are pretty provisionary, and are still subject to alteration.
Likewise, status effects could work as follows:
Small - works on invertibrates and those without strong internal structures [bugs, abominations, plants]
Confusion - works on those with simple minds [birds, beasts, bugs]
Berserk - works on those with aggressive inclinations [wyrms, bugs, abominations]
Stop - works on the relatively immobile [robots, plants]
Slow - works on the heavy [robots, some wyrms, huge plants]
Silence - works on those that can speak [humans, wyrms (intelligent dragons and serpents)]
Sleep - works on those that *can* sleep [humans, wyrms, beasts, birds]
Dark - works on the diurnal [birds, plants, beasts]
Petrify - works on those that live in the earth [plants, abominations, bugs]
Paralysis - works on those with complex nervous systems, even non-biological [droids, humans, wyrms]
These are all very provisional. And, in part, it's up to you to tell me what you think. Your feedback could have a real impact on how things turn out, so get typing!
Humans weak against Holy sounds like a statement about the nature of Man, haha. I can't argue about the convenience of balancing the elements to 2 weaknesses per class, though. If it weren't for plants and insects, I'd say humans could be weak vs. fire (due to clothing usually being flammable), but then again it wouldn't be very smart to wear flammable material in a fight involving magic.
Of the arguments for status effects, Sleep's makes the most sense. It still seems like a lot of those statuses should work on humans, but it could be written off as Shinra soldiers coming prepared with a status-protection accessory (since it's not like they're uncommon).
Was also thinking of
Beasts - weak to FIRE; resist ICE (warm blooded vs...
Wyrms - weak to ICE ; absorb FIRE (...cold blooded)
Birds - weak to WIND; nullify EARTH (airborne vs...
Plants - weak to EARTH; nullify WIND (those rooted in the earth)
Mechs - weak to WATER; absorb BOLT
Aquatics - weak to BOLT; absorb WATER
Abominations - weak to HOLY; absorb POISON
Humans - weak to POISION; resist HOLY (they aren't sensitive to the planet, see?)
I'm still a bit unsure. Most insect models have wings, so could include them with birds, or just leave them neutral.
I like that second list of elemental affliction much more, though not sure about Mechs absorbing Bolt. I mean, it makes sense, I think, but we've grown so used to Mechs being weak against lightning.
But ya, I like your system. Great 2nd list.
I'm pretty sure humans are easy set on fire and struck by lightning!