The flip side of this "don't start with too small a canvas" idea would be exemplified by the B-52. It started life as a no compromise high altitude strategic nuclear bomber, but by luck that required a lot of wing, a lot of load, a lot of range, and, at the time, a lot of crewmembers. This abundance of thrust, payload, wing area, electrical power, and flexible internal volume has proved extremely useful over the six decades of the plane's front line service. Hound Dog, SRAM, Quail, Harpoon, CALCM, ALCM, most models of gravity nuclear weapons, deep earth penetrating munitions, JDAM, Small Diameter Bomb (SDB), and all manner of new smart munition, iron bomb, cluster munition, etc have been carried inside or outside. The "big belly" versions carried up to one hundred and eight MK-82 500 lb bombs, delivering them with precision in any weather long before there was GPS. Today, with SDB, it is the most effective close air support platform in many situations. A Vietnam-era soldier would be amazed to hear that, but it puts the ordnance exactly where the guy who knows best--the guy on the ground--specifies. And it can stay on station continuously with enough ordnance to make a difference.
Technology changes-- the tail guns are gone, but that freed up more payload for coming hypersonic weapons. And when the technology pendulum swings back and GPS is vulnerable, there's room on the B-52 flight deck for navigators to use sextants (again) and for any gear and crew necessary to get to the target autonomously. Maybe up high, as designed, or more likely back down in the dirt like she did for decades. There's real estate on the plane to adapt to a changing environment.
Nobody planned it from the start, but it has worked out very well.