Apps that are pay-to-play but are not 100% upfront about it should either be properly labelled as a demo or rejected. (Of course, before that we need a proper demo mode for freemium apps). I would disable for kids but not for me.
Ads are ok, but apps with ads should be properly labeled and there should be a way to avoid seeing those apps in the store. And ads include the "install chains", of course. I would 100% disable those for me and for the kids.
Notification spam should be dealt with the same way we deal with email spam: transactional is ok, for unsolicited marketing messages there should be a way to permanently unsubscribing. And mislabeling marketing as transactional should be grounds for rejection. I wouldn't ever accept marketing myself or allow kids to receive.
Privacy violations should be grounds for rejection, period.
