Seems a little inefficient, especially in ship layouts similar to the constitution class, to have those relatively long plasma conduits between the major components of the drive system. There's no obvious staging mechanisms along the conduits in most ship cutaways I've seen.
Do M/AM reactions create some local disturbance that upsets fields around warp coils or the transfer of energy from the plasma to the coils?
Is there some warp coil damaging particle by-product of the M/AM reaction that must be allowed to decay before the plasma reaches the nacelles? (ie. something more than the stream of photons that present days physics predicts as the only product of a 1:1 M/AM reaction)
You'd think that powerplants mounted right in the nacelles would be the way to go (as it may be in some ships, perhaps with different power sources) if there wasn't a functional reason not to.
Any thoughts from the community on this?