Skipping on impulse engines because 'we have Warp Drives' is a sure thing that will cost us a ship.
It's just a few more industry points to add, yet some still feel they want to shortchange the ship and its future crew.
Whilst I don't agree with it, I can see the argument against torpedoes if people are really committed to it for cost reasons, although I think it would limit the class's viability as a scout in the next war we find ourselves in. (Extra phasers are easier to retrofit on.) But losing on impulse power, especially when it costs Civ Ind and not Stf Ind, seems like a big mistake to me.
Torpedoes take up space that can be used on Science modules. We do not impede the science. No Torps.
Just to be clear- if it took up space, this would be listed, as options which reduce internal space have been listed before. If you don't want torpedoes, then of course I respect that, but this specific reason is not true as far as I understand it.