What are the issues? I've been considering getting a Nexus 5, but I don't use any Google services (perhaps besides the Google Play store). Will it be a brick?
The only pain point you can have is if you refuse to use Google Play for installing apps. Well, Android allows you to install apps from third-party app stores or websites (e.g. Amazon's App Store), but most devs are on Google Play.
I'm a heavy Google services user, however I'm using lately K-9 Mail instead of the GMail client, because K-9 does encryption. I'm also using OsmAnd+ in addition to Google's Maps. I don't even have Google+ installed (though I do have a Google+ enabled account).