I haven't looked at Metal's API. I have programmed PS1/PS2/PSP/PS3 which all used command buffers completely under your own control letting you pre-create them and removing all overhead for "Draw Calls" so I'm excited about these new APIs that seem more like consoles.
There are several demos shown which demonstrate the advantages of getting rid of the draw calls. Not only can you draw a bunch more stuff but you also get much of your CPU back to do other things.
The showed one example doing 400k effective draw calls on some tablet which would be impossible with the older APIs.
I found this Vulkan video from Siggraph exciting
https://www.youtube.com/watch?v=quNsdYfWXfM
There are several demos shown which demonstrate the advantages of getting rid of the draw calls. Not only can you draw a bunch more stuff but you also get much of your CPU back to do other things.
The showed one example doing 400k effective draw calls on some tablet which would be impossible with the older APIs.