Dynamic Memory - pay for what you use
On premise we use Dynamic RAM on Hyper-V. It would be useful if the same applied for Virtual Machines on azure and we pay based on the amount of RAM used.
This makes choosing the VM size easier and makes things more cost effective over a period of time.
This is tricky to offer given some of the bin-packing needs of offering a public cloud service. We will continue to investigate the possibility of doing something like this.