Twilight Princess being my favorite game in the franchise, I did like Wolf Link. BUT after a while, Wolf Link got annoying. I liked that they brought something newer to the game, just like they did with Deku Link in the beginning of Majora's Mask.
I liked him a lot,if I had to play the game from the beggining to the end,having to play as normal Link,having to walk each hyrule field or gerudo desert,it would be really boring to walk slowly on large and extensive areas.
As awesome as he was, it is very clear to me that the developers heavily under-used him. I was anticipating seeing puzzles in the later dungeons where you would have to switch back and forth to find items, but there was nothing of the sort. Great idea, bad execution.
I thought he was great. He looked amazing and was fun to play as since there were new ways to solve puzzles and he allowed some fun exploration. I felt that it gave Link a little more depth as a character. Plus fans have loved transformations ever since Majora's Mask, so Wolf Link was epic.
He was a great addition to the game, definitely created a more creepy mood to TP. When he first transformed to a wolf, I was scared like heck xD. He was very fun to use too, except when collecting tears, cuz the twilight zone is just scary xD. He made traveling easier and it was fun going around towns scaring people . Kinda off topic, but Wolf Link is also a very original idea, one that most game creators have not thought about, so the originality is definitely there, unlike most games nowadays.
I think it added another concept to the gameplay of TP. Not only did you have the attacks and abilities of Link, but you also had to learn/use the attacks and abilities of Wolf-Link. This allowed for a much more diverse range of gameplay over the course of the game. Also, it was just cool.