We don't really know squat about how warp fields are created. There's no obvious need for two nacellefuls of coils, that much is clear, since most ships don't have any nacelles at all. Only Starfleet's designs and certain select Klingon and Romulan ones seem to favor the two-naccelle setup, and there doesn't appear to be any  maneuverability handicap or anything for those ships that don't.
 
So the idea of having "double hardware" inside one nacelle seems unnecessarily complicated. A single row of warp coils should work all right.
 
Timo Saloniemi
	
		
			
		
		
	
				
			So the idea of having "double hardware" inside one nacelle seems unnecessarily complicated. A single row of warp coils should work all right.
Timo Saloniemi
				