Personally, I don't have a problem with FBS schools scheduling 1 FCS school. That's 1 game out of 12.
I agree. There are arguments to play one if a school so chooses. Sometimes it is about finding an opponent for an open date. I also like an FBS school from a power conference, to play at least one other BCS-type from another conference.
Sometimes a school backs out of a contract late to schedule another, and the opponent is often left scrambling for somebody for one available date. Also, those power schools are looking for seven or so home dates per season for their fans, more TV coming to town, and money.
While I think it is inappropriate for a strong program to schedule three or four known cupcake OOCs' for a season if tougher choices are available; allowing a school one or two flexible games, as each school may see its needs, is not necessarily a bad thing. For example, if Clemson wants to play nearby Furman some seasons, there can be certain mutal benefits.
However, there is always the risk of upsets (i.e. Michigan vs Appy State, and some already this season). Never a good idea to schedule somebody freely that one can't afford to lose to. It can get certain coaches a long way toward getting canned.
There's already a uniform policy on FCS scheduling as to how many games may count in power ratings. It is one.