My experience with azure storage didn't make me think it was "designed"...
Evolved via natural selection perhaps?
Azure storage is definitely the black sheep. They cleaned up the VM/compute layer a few years ago with the introduction of Azure Resource Manager (ARM), but storage hasn't gotten that big an overhaul yet. And it shows. They seem to be slowly improving things under the hood though...
Hopefully they’ll eventually provide an S3 compatibility layer like everyone else.
Give Azure NetApp Files a test drive. World of difference.
What's the issue with Azure Storage? It seems to me like it's one of the azure cloud services that are the least painful to use - at least through the official SDKs