I was thinking about MT alot today, and I think I came up with an idea to fix it. Currently motion tracking is just broken, because for the res it costs, it is a rediculously overpowered upgrade. Not only does it make vanilla skulks much easier to kill, but it is the best counter for 3 alien upgrades, silence, cloaking, and scent of fear. Instead of just trying to nerf the final wheight of motion tracking, why not make it like an armory upgrade instead? so that at the third level MT is as powerful as it is now, but at the early levels it is restricted to smaller radiuses around the obs and less sensitive to slow speed motion (IE at level one you have an SC type radius that picks up only running skulks, L2 you have a radius a bit larger then a siege that picks up anything with a movement speed, but not still or rotating lifeforms, and at L3 it covers a good 1/4 of the map and picks up any movement whatsoever) Also the cost of the obs should be reduced so it can be more of a common map object, and in turn, becuase you have more obs, the cost of scan should be increased signifigantly, or possibly managed as a pool, where your maximum scan point # is determined by the # of obs you have. In this way a commander would have much more options in terms of stratigic base construction, and motion tracking would no longer be a broken upgrade.
Looking over that idea, it looks like a lot of work to impliment... So I still say fix the frigging onos first.