Hmmm... might sound quite dumb, but what you are saying all the time - This is a high-poly model, but I can easily make it low-poly... Somehow, I haven't seen a single low-poly model you have made! You just say you CAN make it low-poly, but you DON'T! If you really say you can make low-poly stuff too, then please, make the arms low-poly for a small example.
I agree with this guy.
Polycount reducing tools such as 'decimate' are not suitable here:
-The tool works best on reducing the polycount from TOO MUCH FOR QUAKE to STILL TOO MUCH FOR QUAKE.
-The tool has no respect for symmetry and flat details which makes it pretty poor when working with things like guns.
-The tool is designed to help you make lower poly models. Help. It is only a tool and won't do all your work for you. You still need to labouriously correct what it didn't get right and the gun will still need some details that the tool would not have made an exception for.
So it really amounts to a waste of time to make such a high-poly model to begin with, unless your guns are just concepts.
In short, you've yet to show us a low-poly model which takes much more skill than you think it does.
