There is a term in programming, "oversimulation". Shamus Young has a post a bit about it, if you're interested. In general I'd say it's something that has to be avoided. I can't help but feel that designing some kind of "beauty gauge" is one of the lowest posible priorities in any program, only slightly above creating a simulation of your character's digestive system.
It depends on what you're trying to simulate. If you're going for really complex
interpersonal reactions, a system like this may be worthwhile. Although, I will say that the number of variables you'd have to track for a system like this would be staggering, and generate an equally-staggering number of BUGS. On the other hand, if the mechanics were hidden and complex as the OP suggests, such bugs would likely be invisible. But this could be a very bad thing, because it might make the interactions in the game look and feel completely random. How frustrating would it be to decide you want to romance X character on this playthrough, but to discover you can't
because they don't like the tall chicks? Or to be unable to achieve the non-violent solution you wanted because you picked a different deity than on your last character?
If you really want complex interpersonal interactions, maybe you should start assigning characters to be each others relatives, friends, hated rivals, etc. But this would get ridiculous very quickly. If the game is going to feel random anyway, they might as well write the NPC's to believe *whatever* about how your character smells/looks/dresses/acts and just go with it.
Personally, I think a much better method would be to just . . . write complex character interactions. You don't need an unspeakably complex over-simulated global system to do this, but it would help to think of the PC as a character who needs to be written as well or better than the NPC's instead of as a select-o-matic box who only exists as a bridge between NPC dialogs. Give the PC a generic option or two for when people don't like the various personality options, sure. But put that personality stuff in there for the PC.
Here's the kicker--you don't have to get very many
effects from it in order for it to be cool. For instance, suppose in one quest sequence you have to explain some events to several distinct groups of people, and you get options with varying deliveries and degrees of spin. However, have it be that if you do the *maximum* spin, the factions compare notes and consider you a liar.
Here you've established a definite personality and gotten a definite reactive result from it. Then, later on in the game, have ONE callback to it, where you try to get someone to trust you, but they remark that you have a history of being a liar.
It's like callbacks in a comedy routine. They don't have to reference EVERY joke they've made in the routine in order for it to be hilarious. Nor does the game have to react to each. and. every. thing you do in order for it to feel reactive.