First of all i know most of these have been stated. But some are new. In reach i would like a new mode called mapmaker like right under forge on the menu that starts off with an empty grid and u choose the enviroment and such (this has already been stated ALOT) then on forge u put the weapons into that map that u made on mapmaker and some good forge changes would be a 90 degree angle snap and being able to lock things. Lets say u put a crate in the air and lock it. This will keep it in the air. You can lock it by pressing x while holding it and its in those options that pop up. IF u dont lock it, it will fall when the game begins. Also when you keep A pressed i think ur crosshair shuld turn into a little square and u can expand it with the right stick and everythign within the square becomes highlighted. Once highlighted you can pick them all up at once or press X and "copy" them adn can paste once ur not lookign at anything and press X twice.
Map maker can be sort of like halo wars style kind of thing. That would be cool and easy to make enviroments and bases.
Or it can be just like forge. post your opinions and if ud rather have it like halo wars or forge