I just noticed, that the bsa's for Dawnguard and Dragonborn contain behavior files for some creatures (dog, wolf, draugr, falmer).

What if they had continued with more DLC, and had further modified those creatures, maybe in parallel for different DLC? Which behavior verison wins?

For character they always did it "right" and put the (DLC specific) behavior updates into Update.bsa. Why not for creatures?

Ok, I admit. I did blow up the Topic Title a little bit to get attention. Beth certainly had found a way to work that out. Either Steam updates, or enforced bsa load order, or ... But bottom line is, this was not a proper configuration management decision.

And btw. I just released http://skyrim.nexusmods.com/mods/11811 with support for custom animations for all 45 creature races, tail, and 3 plants.

What?

They stopped releasing DLC because they stopped releasing DLC and also probably because issues with getting DLC working on the PS3.

Which is quite unfortunate.

They dug their own grave with that one.

I think you're looking for a developer forum, OP, not a gamer forum. I've seen many developers post here but it's more common for end-users (gamers) to post.

I'm moving this to the mod forum, since it's more suited for a modder's discussion, (they're the people who will be most familiar with bsa files) ...
and you're also plugging your own mod.

The title has been changed to be less confusing.

BGS managed to bork up the howling wild wolves with Dawnguard, making them not howl anymore. UDGP fixes that.

Since one of the patches, BSAs load in the same order as their associated plugins. So whichever DLC (or plugin) containing the behaviour file loads last, will win.