Hey now, we won't be "reducing the game down" in any way, just adding a few beard memes in. That's a bit of hyperbole.
I think if it was actually a part of Dwarven society to respect one's beard then this would make sense. I support the introduction of that to Dwarven culture but we have to get the groundwork in first.
Which is exactly the problem - dwarven culture doesn't exist yet, and all we're going to put into it is a bunch of beard "jokes"?
Toady makes a massive world simulator, and it's all so we can sit around finding ways to make exclamations that somehow involve beards when we could be trying to to actually rationally explore the consequences that would come from living in a world like DFs or expand the genre out of its "All Dwarves Are The Same" trap?
Not a very good anthropologist, are we?
There are many things we can infer about dwarven society by watching fortress mode behaviorisms, though beard maintenance seems more like a sexual attractiveness issue, than a social standing issue. Even so, defacing a beard would be a bit like ripping up a woman's clothes (and forbidding her to get new ones afterward, until she can sew them up herself). Temporary, but intensely humiliating when it occurs, and likely to leave deep emotional scars. The idea is to cause deep humiliation, and challenge the punished's sense of self-worth, as well as provide a public spectacle that the punished will never live down. Alternative for female dwarf might be to glue a fake one on, or promote one to grow somehow. (It being the *ONLY* outstanding sexual dimorphism between male and female body types, you would expect great emphasis on maintaining a beard if one is male, or in preventing one, if female. Much the same way humans find man-boobs repulsive, and facial hair on women repulsive. The whole "She looks like a man!" and "Dude looked like a lady!" thing. Again, since facial hair is the only noteworthy difference externally, since either gender will wear a dress with equal probability (implying that clothing choice is not related to sexuality, but instead just a personal preference, like wearing shorts vs wearing pants) a male dwarf acting "deviant" by being a "Female impersonator" will regularly shave.
(note the scare quotes there. I'm not touching the issue other than the angle of societal mores existing-- not weather they 'should' exist.)
It might seem cliche to keep harping about beards, but then again, it WOULD become cliche about dwarves, given they have no other means of directly ascertaining gender amongst each other, without seeing each other without any clothes on. The beards serve a valuable function to their culture in this respect, and I would expect beards to be flamboyant, and excessive as symbols of male virility. (Also, meticulously cared for. A post-industrial dwarven civ would have huge numbers of beard care products, including things like Rogaine for Dwarves.)
All that being said, Dwarven culture seems very conservative, and thus seems unlikely to institute a socially scarring punishment, over a physically damaging punishment. Dwarves value strength and integrity as social qualities, and that kind of punishment would permanently damage both in the recipient, often in a very permanent fashion. (Even after the beard grows back, the trauma will haunt them forever. It isnt JUST the day the beard comes off, afterall. It is also all the many months, to years, it takes for the beard to grow back in thick and full, and the continual ridicule that will illicit. It's like branding a scarlet letter.) I could easily see dwarves setting up a
pillory in the refuse stockpile as a punishment for minor offenses-- but NOT beard removal. (granted, that would require Toady revamping the thrown item mechanic, so that a fluffy wambler is no longer a lethal projectile at any speed.) Being pelted with rotting produce and rotting giant roaches, while traumatic, doesnt have the same kind of protracted social ostracism that beard shaving would have on a male dwarf.
Other than that, the kinds of punishments dwarves currently DO enact gives additional clues about their culture. For instance, it appears to have a "If you survive, you were clearly innocent afterall" overtone, much like nordic traditions of strapping a woman accused of infidelity to a spinning table with her long braids splayed out-- and have axes thrown at her by her husband. If she survived, and had her braids cut, clearly she was innocent, since the gods clearly intervened. Others include germanic "Marital combat"-- but those were rigged to prevent the woman from winning for the most part. I could EASILY see dwarven society instituting such things as marital combat, without the sexist overtones, to solve domestic issues.