Just thought about the iPad 3 after reading the article. Last time Apple went thicker they created a bastard product that was replaced 6 months later. :-/
More the reason to skip the 6S I think.
other misc posts said:thickness increases almost never happen and are always bad
Not true, more recently than that the iPad Mini 2 was thicker than its previous gen and is a great bit of kit, internally equal to the Air in all but a couple of ways (screen colour quality and speakers spring to mind). It's the generation afterwards that's the controversial one!