the only argument against ayn rand's ideas that matters is that they don't work, even by her own admission. they sound pretty and make sense in your head, it's just not how life works. it never has.
maybe one day it will.
the reason i wouldn't put rand on the list is not that she isn't interesting, but moreso that the majority of her ideas were expressed better first by someone else. very few people really take her seriously. it's like a phase a person goes through on their road to learning. they like ayn rand become obsessed with her, and then move one when they realize it just doesn't work, as nice as it would be for it to work.
but again, mostly because her ideas aren't hers (which if you've read her work is highly ironic). i consider her more of an advertiser for ideas that have been around for ages. a good advertiser, but an advertiser.