Well it all gets down to definitions and its more of a rule of thumb. However, I'm very suspicious of ideas that seem to be good only because the complexity gives them a certain gravitas. Its sort of a version or expansion (or misappropriation) of Gall's law:

“A complex system that works is invariably found to have evolved from a simple system that worked. The inverse proposition also appears to be true: A complex system designed from scratch never works and cannot be made to work. You have to start over, beginning with a working simple system.”

Or "not a feasible idea.. yet", I have some ideas which I definitely do not have the resources to pull off and don't know how to split into small chunks which I can, but I may well have the resources in a year or two, so it might be worth keeping them until then.