This is simply a question for the Xbox/PS3 version of Skyrim, pertaining to Lycanthropy. While looking around, I have seen that at first, you could not be a werewolf again after you cured it- but then come Dawnguard, you get one renewal. My question is why does the amount of times you wanna switch between Vampire Lord and Werewolf have to be limited?

Because the Cure makes you immune to the disease.

Why they allowed a switch for Dawngaurd is more to appease the players who won't make a new character than any other lore related reason.

I'm not sure, but switching back and forth alot probably breaks/messes up other parts of the game. Otherwise they probably wouldn't have limited it.

There's a limit to lycanthropy; from what I understand, you can go from werewolf to VL back to Werewolf, but if you go VL or cure werewolf again, then you can't go back to werewolf.

No.

But there is a limit to how many times you can contract Lycanthropy.

You can continuously catch and cure Vampirism as much as your heart desires. Lycanthropy you only get two shots at it. Once as part of the Companions quest line. then if you get cured, Aeola (sp?) will give it to you once more, and only once more. If you get cured again, you're S.o.L. if you want it back later on down the road after that.

Gonna make a joking guess about the reason, simply because I thought it'd be funny.

Bethesda didn't wanna keep promoting the idea of Aela feeding her blood to The Dragonborn.

That sounds like about as good of a reason as any.