I'm watching the original Arrested Development seasons for the first time. Michael Bluth wears very large suits, which I know was the style at the time but I'm unsure if they're supposed to be coded as ill-fitting or if they're actually nice suits for back then.
I noticed this, too, and I always thought it was a deliberate nod to two major story facts:
- Michael is trying to do his dad's job
- the Bluth Company and family are in dire financial straits
I always felt like the first was the most important. The theory here would not be that Michael's suits are hand-me-downs or cheap, but that the costuming subtly conjures the idea of a kid wearing his dad's office clothing but trying to be taken seriously. The first three seasons are heavily concerned with Michael's efforts to succeed his father, and all the resistance and difficulty he faces doing that. Putting him in clothing that's just slightly too big for him keeps that theme in our minds, and helps us see Michael the way his parents and siblings see him.
The other fact makes for a less interesting explanation: Michael can't afford to have his suits tailored and so is wearing off-the-rack. The first season especially does make a point to show that Michael is frugal to a fault.