I think the key thing to remember, is intake and exhaust areas are very critical to EDFs. The F-15 I mentioned earlier wound up crashing when the owner removed the vecoring nozzles and wound up losing a lot of thrust. I think a bigger nozzle creates more low velocity thrust, good for low end power, to a point. And a smaller nozzle creates high speed thrust. So there's a sweet spot somewhere. I guess it's kind of like the gears in a transmission. I believe shrinking the exhaust nozzle speeds the exhaust to a point, then creates too much back pressure or something, then loses efficiency. That F-15's exhausts were bigger without the vectoring gizmos.
Just food for thought!