I tested this out in the NPBL and it didn't work, but that was in OOTP13 IIRC so it may work now.
I don't think the age limit thing would yield the same results, because if you ran it in that fashion, everyone over 30 would refuse their assignments, while the 'right to refuse' would leave the choice up to the player. That 35 year old outfielder that makes a great pinch runner (but sucks at everything else) during the expanded roster period in September would probably go back to AAA if he could, but with an age limit, you'd have to release him... and nobody would want him on their 25-man so he'd be stuck in the FA pool 'til he retires.
So, I'd probably vote against that rule at this point in time unless you guys can convince me otherwise.
One note; at the time we tried it out in the NPBL the FA pool had about a dozen players in it. That's not an issue in the AFBL (or NPBL for that matter) with the longer draft and other ways for players to enter the league (international FAs).