(Spoiler Alert for people who haven't seen the movie)
I really enjoyed it myself. I thought it was fantastic. I don't care for the constant comparisons to "Tangled", though, that I see most of the time, as if "Tangled" was somehow the "gold standard" for Disney animated films. (And, frankly, if someone is going to point out plot holes in "Frozen", I could go on all day about "Tangled"...plus Disney went WAAAY too expensive making "Tangled" and they were probably trying to see if they could do more with less.)
Did I think the ending was abrupt? Of course. It's my only legitimate complaint with the film. Do I have other more minor complaints? Yeah...but I've reached the point in my life where I realize you can take any movie that's good and find all sorts of things wrong with it, and in the case of a film like this that is meant for all audiences, it's more "forgiveable". And the more you "hype something up" for yourself, it eventually reaches standards no film is ever going to live up to. Chances are I would have hated this movie if I hadn't accepted that it wasn't going to be the original version of "The Snow Queen" long before release. As I had decided to appreciate it for its own sake, I found it more enjoyable.
That said, I overlook the ending because otherwise the plot would have written itself into a corner. Elsa's powers were getting more and more out of control, she couldn't rein them in or stop them, and so if she hadn't had the "Eureka! Love!" moment, the only legitimate solution would have been to kill her.
Ultimately, any of my dislike for the film is overshadowed by the fact that, for once, the theme wasn't a girl finding true love with some hunky male she just met and that saving the day. It ended up being the love the sisters had for each other. Some people still complain Anna ended up with Kristoff...but did she? She kissed him, yeah, but they weren't rushing to tie the knot. The movie ends with Elsa and Anna skating, not a marriage proposal.