But doing that will prevent you from continuing the Dawnguard questline until you are healed of vampirism as well. Personally, I recommend having your soul split before the Soul Cairn, and then having Serana transform you into a vampire once it's all over (the entire questline).
Because crushing Vampire skulls and basking in a holy aura is so very common amongst Vampire Hunters. I am trying to figure out what is so cliche about him. Please elaborate on what makes Dawnguard so cliche. I am having difficulty trying to see this from your point of view.
I agree that Dawnguard vampire side was original. It's unlike any other questline in the game, you experience the intrigues of vampire court, and really get that bloodthirsty vampire feel from it. The Dawnguard on the other hand, I never felt anything holy about them, they were just a group of vampire hunters, plain and simple. Sort of like Companions in terms of feel about faction. The members were not as well fleshed out as vampire clan as well.
Isran's macho personality, have you ever watched Supernatural? Or those older movies like the one where the guy had a gatling crossbow... there's always the macho vampire hunter with a deep voice.
Harkon is also a big Dracula cliché, Serana is 50/50 cliché. But what's innovative about the vampires is that you can actually be on their side.
Dawnguard. It's more fun to me than the Vampire Side.
The "last battle" is much more enjoyable.
Also, I really liked Isran, and his voice. He's not as cliche as Serana's Family*, as someone mentioned...
Plus, the Dawnguard has Beleval and Florentius. I loved Beleval.
*However, I loved Harkon's Court, mainly Fura Bloodmouth (much better than Serana, in every way), Garan Marethi (Dunmer, House Dres, and I felt like he is the only one who likes you, trust you and respect you. Always my right arm) and Feran Sadri.
I've played both sides, and it really depends on what type of character I'm playing. If I'm playing a thief/assassin/evil type character, I generally go with the Volkihar vampires. I love the castle because of the atmosphere. It really does feel like a gothic castle, and the court is interesting.
The Dawnguard side is also fun, and in my opinion, the final battle at the end is more satisfying on this side. I also love the huskies. The trolls would be cool if they weren't so stupid half of the time and not even attacking enemies.
Overall, go with whatever side you feel most interested in. You could always save your game before making the ultimate decision. This way you can try both sides on the same character and see which one you enjoyed the most.