In a world without sunlight...

[Rampant]

Does mage armor increase check penalty? make it hard to change clothes? or impossible to eat? No?

Assume it's user friendly.

Furthermore if the druid can be a badger couldn't he hollow out a temporary space, and then turn into something stronger, push the wall down, and then badger his way back out?

 

[Greenfield]

He's a Ranger5/Druid 5 and gets one change a day.

Does Mage Armor keep you from changing clothes? No. But I'm not sure just how user friendly it is. I mean, your argument is persuasive, but there's a big difference between fitting clothes around/through, and pushing it completely through a wall of collapsed earth and stone. I'm not sure I'm persuaded.

But I'll think about it.

 

[Rampant]

Does the description ever say it interferes with movement? i mean if a caster with MA up uses gaseous form he still gets the bonus doesn't he? even if he moves through a wall.

You're looking for a rule conflict where there is none.