Jakeblake You can try to make the thrusters look better by mixing together the different sizes of thrusters into a "composite" thruster. The engine when it fires also looks less repetitive by doing this. Of course, this is less efficient but there will pretty much always be some efficiency loss in trying to making a ship look good.
Here's a ship where I've mixing together the different sizes of thrusters. I think it looks 'less bad'. I guess it depends on how fussy your are.
