I'll probably get flamed for this, but I definitely see and agree with where AA is going with this. I don't think it is a good idea (from an airline's perspective) to allow BOTH one-ways and stopovers in the same award. Sure, some say it costs AA nothing, but that may or may not be the case, especially with partners. Fact is, if you start allowing one-way awards with free stopovers it could get out of hand quickly.
The point of an AA or all-partner award is to allow you to travel using miles from A to Z. If you want to stop at B, C, D, and F then you have those options available to you (OneWorld Award) or *gasp* pay for the ticket with $$$. Just my .02