I went back in forth on Elend throughout the books. I didn't like him becoming such a powerful Mistborn all of a sudden. I mean, I understand why it happens that way and whatnot, but I'd have preferred if Elend had remained a 'normal' human and left Vin as the only Mistborn in the group-- I mean, honestly, Elend being a Mistborn didn't add much to his story aside from a bonus of 'oh Elend is so good and pure and true and now he is a mega-Mistborn on top of it'. I felt like there was more time spent with other characters telling us that Elend Venture was this great person than us actually seeing Elend himself being that great. I don't think he was a bad guy by any stretch and he did grow up and into his role as king. But I just don't think he was as good as the others made him out to be and would have preferred to either see them (especially Vin) acknowledge his flaws instead of defending him as such a great man whenever someone did point anything bad out.
I didn't particularly like the development of his relationship with Vin, for that matter. But from what I've seen thus far (in the original Mistborn trilogy and the first 3 Stormlight books), writing romances is just not Brandon's strong suit. Elend and Vin weren't bad together or anything, but they just didn't really grow and develop as a romance very organically, in my opinion.
Since I am not 100% on the spoiler rules of these forums, I'm putting the below part behind tags just in case, but it pertains to Elend compared with a Stormlight character. I don't think anything I say in here is that spoilery, but just in case you haven't ready Stormlight yet and don't want to read anything related to it...