Because Vampires are able to use their perks in the normal skill trees. Werewolves in form can't.

But Sinding was affected by Hircine's ring. I don't think Skyrim does away with the savage/bestial werewolf entirely, but it seems to marginalise it at least with the Companions and the player not being an uncontrollable murderous beast. But Skyrim's version of the werewolf does seem to be generally more intelligent than say the werewolf from An American werewolf in London or other horror films.

The point of curing yourself of Lycanthropy is to not be a Lycanthrope again. There is no point to being able to redo the ritual. Plus, eventually There are only so many witch's heads btw (5 in total, 2 for the twins and 1 for Kodlak)

No, Lycanthropy curing is a one way street and should stay that way, but you should be able to jump very high, hit with the fury of an South Central pimp, and be able to take on several enemies at once without much harm aside from silver and daedric weapons.

Lycanthropes should also be allowed a perk tree

They could actually give you reasons to want to use Beast Form at higher levels, for starters. I've never used it because of how much it can cripple you, considering you can't drink potions while in Beast Form, and not to mention that last I read, Beast Form was bugged and had practically no armor.

Yep, i think it would be easier on the eyes if you don't.

No, Beast Form is influenced by light armor, which is weak as it is.

By the way, if they would put in some kind of perk tree for werewolves, would they also raise the level cap so high-level players could get the new perks? I'd hate to start a character over just because I couldn't get the lycanthropy perks. Obviously in that case the developers should create some other new perk trees for other players.

Strange. After all this time we finally have werewolf NPC's in the wild? Is this a mod or not?