OK, so by RAW, the Vampire has a moderate allergy to sunlight and a severe allergy to wood. It seems to me that it should be:
Severe Allergy: Sunlight, (meaning the sun will actually kill them.)
Mild Allergy: Wood (which would keep the vampire dead as long as the steak was through his heart).

That seems to agree with most representations of the vampire. Is there a reason it would be different?

Also, what is the meaning/point of "induced dormancy - Lack of air"?

The Nosferatu brand of vampire have the severe allergy to sunlight. Might be regular vamps have moderate to flavor them a bit differently. As for the induced dormancy: it means they basically go into stasis if they lack oxygen. The point? I can only speculate, but it lets you have vampires hidden in weird places. Like at the bottom of the ocean, or in a hermetically sealed container.

It's just part of the mythology. You can 'store' them in a coffin, etc. indefinitely.

I guess that's what I figured.
So, unless there's any good reason not to, at my table, Vampires will have a severe allergy to sunlight and a mild (I wish there was even less of a level of allergy) allergy to wood.

How 'bout garlic, running water and other such things?

Shouldn't work. Remember, the vampires in this game are created by a virus, so a lot of the mythos around traditional vampires wouldn't apply. I guess if you wanted you could have them allergic to garlic as well, but I'm not sure how you'd manage running water.

Mild is pretty damn mild, as far as the allergies are concerned. Just means they are at a -2 to all actions and can't regenerate.

Not regenerating is a really big deal if you regenerate. I was going for the idea that wood doesn't really hurt them any more than anything else does, but if you "kill" them with a stake, and leave it, they'll stay dead.

It's a magic virus. Magic is arbitrary. So they left out garlic, kept in wood, etc.

I dunno: could anything be more 'stop regenerating' than 'stay dead', Bearclaw?

The 'induced dormancy' and reduced boyancy would be the explanation for the fear of running water. The vampire can't swim very well, and being swept under water would mean falling comatose, so they would likely not risk crossing a stream.

There's some precedence for vampires having a psychological allergy to holy objects - you can easily do the same with garlic. Certain vampires expect to be allergic to garlic, so they are (In Bram Stoker's version, it's garlic flowers though - not garlic itself).

Previous editions had higher allergy levels for Sunlight, but there was a category higher than Severe then, which Nosferatu had.

The 'burns up in sunlight' thing is very new as far as vampire myth goes: 20th century, mostly. Older versions had stuff like blistering, or nothing but their supernatural powers not working.

Note that regeneration isn't as powerful as it seems. It's not your typical DnD thing where they can keep coming back. All it means is that they heal pretty damn quick, according to their magic rating. Once you fill that phys track, they stay down. So if you kill them with anything, they stay pretty damn dead Playing on their allergies just makes them go down that much easier.

I get that. The point is, while thay can take a hit from a lot of stuff and shrug it off, a wodden stake will kill them.
Regeneration even works in overflow, right?

Yes. Even when their overflow is full and they should be dead, they still get 1 regeneration roll: if that brings them back to "not dead" then they recover (otherwise they stay dead).

So, again, it kinda feels like the wood allergy is the exact mechanism you'd want there.

Yeah, I think it works even in overflow. I guess I just don't see the need to nerf the wood allergy,really, but thats up to you. I figure if you're close enough to stake him, you're close enough to put two rounds in his brainpan and push him past overflow. Unless you're an archer using arrows with wooden shafts, the wood allergy will rarely come into play.

Most coffins are made of wood. All kinds of stuff cool rich guys in 2072 have around them is made of wood. It's OK if touching something makes him itchy, but not OK if it makes him smoke.

Ah, I didn't know you wanted to push the traditional angle that far. I'm not sure why they'd WANT to sleep in a coffin, considering how comfy beds are Even assuming most coffins are made of wood in 2070(not a guarantee, considering the popularity of synthetic materials), I would imagine theres enough of a lining inside for it to not be an issue. As for rich guys....wear gloves when touching that mahogany desk?

I don't think severe implies they start to smoke; they might just blister or puff up like a bee sting.

It doesn't matter if you push him past overflow though - he still gets a regeneration test to try and survive at the end of the turn.

Yeah, Regeneration was much better/worse in SR3.
One Roll and if you succeed, you are healed to perfectly fine immediately.

Entirely possible I need to brush up on my regeneration rules, then

Note that there are two different types of vampires represented in Shadowrun:
"Vampire": The Bram Stoker Dracula vampire. Like the original Dracula, sunlight is merely an inconvenience to him that suppresses most of his powers.
"Nosferatu": Based on the German Dracula ripoff, featuring Count Orlok. This was the first vampire story where vampires actually burned to a crisp in sunlight.

TL;DR: The allergies are fine.

Um...

Why would a vampire have any less buoyancy than any other metahuman? I'm not understanding that.

I mean, sure, I can see getting swept under the water and going dormant sucking big time, but it probably can't suck any worse than, you know, being killed by the process. And normal metahumans are willing to risk that when it's necessary.

Coz RAW says so...and vampires probably are a somewhere between haggard and emaciated unless they only feed on victims with crazy cholesterol levels