The +2 partial plate was just the most extreme example of armor offered to them. Let's see, there was the +1 scale mail, +1 chainmail, +1 (or was it +2) leather (which was used), I think that's it. I can understand the Rogue/Wizard not wanting the medium armor, and the Monk and Sorcerers not wanting any of it. The Cleric of Kord has pretty much rejected everything because of encumbrance penalties (as far as I can tell). The Ranger has rejected most of it because of his 19 Dex. The Fighter who has rejected it all, well, I am not sure why he won't take it.