Well, i have to agree with your 'new wife'
my oscar tanks have been bare bottom too, and mainly for same reasons, I think the oscars just make too much waste...i've used gravel and gravel filters for small fish ok...
I also agree about not keeping other fish that might bother the oscars, I think they can stress each other enough as is, they don't need no strangers! Well if they can easily fit the 'strangers' in their mouth for dinner guess they wouldn't mind that