I absolutely Love Serana, for all the above mentioned reasons as well as the fact that she is voiced by Laura Bailey, who I have adored since discovering her when she voiced Bloodrayne. Met her once too, at the Kawaii Kon 2009 in Hawaii. But I understand why they didn't make her marriageable, they didn't want a repeat of Aela. She was a strong werewold huntress, then you marry her, and she's all domesticated and toned down, but if they do make Serana marriageable, they've got to keep Serana the same, not domesticated. I wish we could marry Injard, the Dawnguard Warrior. Or even Karita from the Dawnstar Tavern, since she's got the most gorgeous voice out of all the bards, even better than Panrea, who claims to be the best *rolls eyes*
Also, I'm having trouble getting the dialog option to propose to Serana, as posted on UESP, they say it can only be done after completing "Beyond Death" But I've never gotten the option. I make Let's Plays and I want to showcase her rejecting the offer, and I've yet to find a clip of it on youtube. Anyone know the exact specifics of getting the option? I got the Amulet of Mara equipped when I talk to her, but nothing.