You're definitely entitled to your opinion. But I found the initial run of Arrested Development to be one of the best written sitcoms ever. Also, part of the point is that the main protagonist and his son are good people who stay and support their terrible family members out of loyalty.
I would characterize Michael more by his self-righteousness and ego-driven attempts to be good than his actual goodness; so many of the show's hijinks stem from his savior complex bringing out the hypocrisy in his attempts to be 'a good guy'.
To be clear I think it adds to the humor, not complaining at all. Horrible people being horrible makes great comedy and Arrested Development offers far more than just that (probably my favorite comedy show). But it can get kinda depressing, if I'm not in a great mood I can't take more than a couple episodes at a time.
Michael being self-righteously and self-centered-ly good, and everyone else being earnestly and obliviously (and maybe even endearingly) terrible sounds about right. :)
Sometimes there's some elements that really shows the potential and brilliance that is interesting enough to keep pushing forward. So while it might not hit the point of must see TV right away, going in with the knowledge that it hits its stride in season X helps keep things in perspective. When I'm informed of something like that I'm willing to put up with the slow burn if the pay off is to be great, and there's at least some redeeming qualities about the show until then.