If being " wild " is the issue here then why do the Companions live right in the center of Whiterun?
The Companions are human (most of the time), and use their beast form when out doing certain types of mercenary work (or whenever they feel like going out on a hunt). They are also capable warriors in their own right. Mercenary work is better suited to being a werewolf since you'll often be working alone in various remote places. That's very different from the Dawnguard, where it appears you're working with a group in a specific fortified area.
The Companions also had a deal with the Glenmoril Witches to have more control over their form, while promising to serve Hircine in life and in death.
Which leads me to your other point, I think a lot of people are too stuck in the "lore" of TES. Lore changes with every generation, which is probably what Bthe is trying to do here. Both factions in the up coming DLC have not been encountered before, both have just appeared out of no where, add this to how the trailer looks and to what vsions posted in my topic and it just screams vampires vs werewolves.
I have no problem with the lore being altered if it's A) a plausible change, and B
) makes the world more interesting. Vampires vs Werewolves isn't interesting, nor would be the lore changes to make it happen. The plausibility of such a change would also be in doubt, given what we know about vampires and werewolves.
And yes you are right there, but once again, mixing two dominate predators together is like mixing oil and water, it just doesn't work well together.
Though that's only an issue when they're in the same area with the same food source. So far from what we've seen, this doesn't seem to be the case. Consider also that werewolves, in addition to being rare and thus not likely to impede on the same area as vampires, are in human form most of the time and only need to kill people once or twice a month.
I'm not saying that you guys are out right wrong, chances are I just might be wrong, but I'm not out right dismissing your ideas based on the fact that " I don't think the lore should/will change ".
I'm not dismissing the ideas based on the reasoning "I don't think the lore should/will change". I'm arguing against the idea because I'm tired of werewolves and vampires pitted against each other "because it's cool", and by extension wouldn't like any lore changes made to try to justify it. It's an overdone trope that I'd much rather see fade into obscurity than to catch on in yet another piece of werewolf- and vampire-related media.