Given this is a thread on cockpit interaction it seems pretty clear to me that a cold start involves the player doing everything the real pilot and in some cases ground crew might do to get the aircraft started. Which requires the options for either clickable cockpit or mappable controls. My preference would be both.
Mission designers can opt for what they want but the options need to be built in to sim.
IMHO the player should have access to quick missions that don’t touch the mission builder to be able to start in the air, on the runway or do a full cold start with full interaction.
It is a curious thing, MSFS leaves me cold (no pun intended) without the combat element, yet I can often find myself using DCS to fire up an aircraft and simply take off and land. I can get great enjoyment from doing that but it wouldn’t be what I would expect to be my requirement from a combat sim. Sometimes it seems I spend more time mapping controls than flying a new aircraft to get it perfect but although it might seem a chore the results are worth it.