I think it depends on which of the planet side missions you do, Some are relatively easy you scan some new life forms find a few more and been back to the ship.
Sometimes you might have to fight and yes it can get abit frustrating as the emmey have a tendacy to run toward you at point blank range and you ether end up with your caracter being held while the fire the crap out of you, Or you end up having to try and back away from them and the carmera angle changes so you cant see what your shooting.
I agree that if you could actual come up with the stratergy for how to take them on and if there was more varied landscapes with more structures to hide and crouch behind. Bu i still think the biggest problem is the AI. Being able to use a phaser rifefile at long range to kill an emmey would be a grat idea the problem is once you shoot one the rest come charging up and you end up with a very annoying bit of gameplay.