iCloud Backups and Storage Limits
I agree with the sentiment expressed by Nik Fletcher and Shawn Blanc about iCloud backups for iOS devices. Apple should step and own these as an invisible part of the ecosystem that 'just works'. These shouldn't even appear in your iCloud quotas at all.
My wife's 32GB iPad 1 and 32GB iPhone 4 overwhelm her base iCloud storage. My own iPhone 5 64GB and iPad 2 32GB were making do on my 15GB iCloud storage, but I recently had my iPhone 5 replaced and will be transferring it to my wife when the 5S arrives, so at the moment iCloud has two iPhone backups that I haven't sorted out, and in the meantime I get warnings that my phone couldn't be backed up completely.
In my case and my wife's case, we know what our options are, but it's a bit of a pain to sort out and in the meantime, neither one of us has a completely ideal mobile device backup.
It certainly gets worse if you have a 64GB iPhone and a 128GB iPad, which Sean Blanc points out is well above the maximum 50GB iCloud storage option.
If Apple isn't willing to foot the bill for iCloud backups of iOS devices, then they should offer another solution, like support for doing full wifi iOS backups to a Time Capsule, which would require a little more setup, but at least offer a solution.