I fully expected the majority of the characters to be half-assed going in and was pleasantly surprised for most of them so I suppose that had a big influence on me not minding their portrayal. Also, like Hef said, they really could not go any lower and had nowhere to go but up as it was. I really loved the main characters and the direction so it was mostly a win for me. I cannot honestly say that I noticed the CGI being anywhere near 'bad', but maybe I just need to watch it again, it's been quite a while. As far as most films go, especially action flicks, I can't possibly imagine it is anywhere near being in the realm of the worst offenders. (Sup, Green Lantern?)
I gotta say though, unless they screw up Magneto and Xavier, who I'm pretty much just watching these movies for, it's going to be a win in my book. Also more Quicksilver cannot possibly be bad with how beautiful his DoFP fleeting scene was.