With this perk tree for werewolf we no longer need another dlc for werewolf. we have already the companion's questline and now this buff in dawnguard... for the next dlc no more werewolf/creatures but other things, and go to other places and provinces...
There is always room for a little more improvement if necessary, though, and while the perk tree should satisfy many complaints about werewolves, it won't end every complaint, like the inability to become a werewolf outside the Companions and being able to become a werewolf after becoming cured.
But we have already the companion's questline, Bloodmoon from Morrowind, Hircine's quest, Dawnguard buff... how many?
Next DLC Next thinghs. (i hope for new places in Tamriel)
(I state that I like dawnguard and werewolf)
Why are you using content from other games in your argument? I agree that werewolves don't need a whole lot more content for Skyrim, but not everyone's going to be willing to play an old game like Morrowind just to gain access to werewolf content.
That said, they can now focus on other hotly demanded features, and possibly on the side they can address other complaints that don't really need a whole DLC revolving around it, like for example new armor sets, more spells, werebears, spears, if there are further complaints about werewolves, they could get addressed if there's time, etc.