You are missing the entire point. It is fun, entertaining, whimsical, even throws you off kilter a bit, but that's the joy of it. The sometimes silly, sometimes touching, sometimes strange dialogue is enjoyable; nothing about the show says anything about trying to be realistic! It's fiction, even if it covers interesting, real-life topics.
What you missed most embarrassingly is the fact that they never try to give a clear-cut answer - each episode presents an interesting topic (or two), and shows the alternative ways of looking at it, without ever trying to resolve or find a conclusion, since most of these debates have no resolution in sight. The show explores the delightful complexities of life as we know it, meanwhile being a (as often said) refreshingly unusual mix and vision. The show over and over brings into question anyone's right to claim a 'slam dunk of righteousness'.
I think being 'all over the map' is an excellent challenge - and having cliche characters doesn't hurt it, since in many other ways the show is trying to create something new, even if it's a hodgepodge type of new. I'm tired of style being so consistent within a show - it's great to only have to watch one show but experience many emotions and styles! Sometimes a mish-mash is fun, and many (including myself) think they've done a lovely job. ABC will be shamed miserably if they do not bring it back for another round.
Oh, and by the way, Miller is great. He plays this extremely unusual and complex (as you yourself wrote) character with gusto and sensitivity. Kudos, but not to you Werts.