Make it easier to create an instance within a non-default VPC/subnet

[emilyalbini]

The instance creation page allows you to either create an instance in the default VPC, or to create a whole custom network interface. If you want to create an instance in another VPC you are forced to go through the custom network interface. It'd be nice if there was an easier option for that.

[david-crespo]

Notes from chatting: if you conceive of what you're doing as "pick a custom VPC" you would never know to go through custom network interface. And then once you figure that out, you have a whole form to fill out.