probably it could be done in a way it would look good but it would require a lot of work and i don't know if someone would get to it and also if there is anybody who is still makeing mods for this game
Well not exactly copy n paste the synth skins over to the marine model.. but you can still cut n paste the face.. kinda.. or at least some parts.. I just think a Synth skin + synth sound pack would be a new idea.
problem is that the texture of synth does not mach the texture of marines so you will need to put the right thing on the right place. and the worse part is that we cant change models and just with changed textures it will not look good