writing rambles

I am trying to finish off my first Tolkien reverse summer bang story, which is about a slight AU Idril and Tuor.  I hadn't written Idril before (have written Tuor before, but he was a sealion skinchanger then, so arguably not very canon either!) 

I like the idea, and I'm over the minimum word-count, but somehow the story hasn't quite taken wing. 

I think what I'm struggling with is that Tuor and Idril have neither of them done a thing wrong in their entire lives, so far as I can tell, and are also enormously competent. I do like a competent character, but a character with weaknesses is perhaps easier to relate to.   Or maybe it's just a 3/4 done stall and I just need to get the end of it finished.