No, the question is neither of those. The question is how to define the cutoff in a portable way that enables interoperability and long-term stability. A document format where every implementation has its own secret cutoff that also probably changes all the time is just idiotic if your goal is interoperability.
VPC-only sounds like a giant caveat, and it is, but this is a good opportunity to note that this is the trend now with AWS and the direction they're heading - (non-VPC) "EC2 Classic" is being gradually phased out, VPC is now the default for new accounts, and most new features are being added only to VPC. So, time for everyone to start thinking about migrating.
AWS recently announced ClassicLink , which helps with migration: "In order to allow EC2-Classic instances to communicate with these resources, we are introducing a new feature known as ClassicLink. You can now enable this feature for any or all of your VPCs and then put your existing Classic instances in to VPC security groups."
They will hopefully introduce a new "classic" (as an abstraction over VPC) at some point, unless they want to lose many low-end customers to "easier" clouds.
Having this level of control can be nice, but most of it really needs to be optional because for most deployments it does nothing other than add an excessive amount of unneeded complexity.
Some of the APIs are outright hostile, e.g. 'delete_vpc' which makes you track down half a dozen dependencies (without providing hints about which those might be) before you're allowed to delete a VPC.
> unless they want to lose many low-end customers to "easier" clouds.
I've never gotten the impression that AWS is interested in building a 'cloud' for those less technically inclined. Heroku and others fill that void, EC2 is where you move after Heroku doesn't fit the bill and before dedicated hardware does.
I did by buying EXAS when the new CEO came in at about $2. The previous management didn't have what it took to get it off the ground. The availability to buy the test came out this quarter so sales numbers are not in yet (but it is fully reimbursed at ~$500, where management said they would make a killing at $300). So after doing your due diligence, it may be worth waiting for the sales numbers to come out and buy on any weakness.
The other way to take advantage is to get yourself screened :)