As a fan of ALTTW and Joe M. in general, I really appreciate your post. The great screenplay and direction make it one of those chestnuts that demand to be watched in their entirety, even when you tune in and swear you'll only watch for a few minutes. A great comedy, it was also an insightful homage to the institution of marriage (and economy) in post WWII America. And every line of T. Ritter's is a scream!
As for being musicalized, three intertwined stories each with a different style, sure. But you need the recurring/common theme to bring together the three couples together. And would Addie Ross only be a voice over, or a visualized character. Food for thought.