I think lego has done a good job so far in the lotr theme, if u buy helms deep, uruk hai army and orc forge you should have 11 uruk-hai. obviously that isnt the same as the minifigure 5 packs people would like, but I'm sure those will appear at some point.
Also good on Lego for not jumping into all the stuff with the orcs in first wave. It would have made the amount of both orcs and Uruks much lower.
As for your MOC it looks good, I'd prefer it in darker gray.
You should use a bigger plate for the base (maybe 4 of the plate you're using now) so when you put togetehr a whole bunch of them they make up the room with the floor.