Even throttle control may not be required, since there isn't any combat/dogfighting in this game where you need quick changes in throttle.
For real though, the landing is where you need the most precise control over both your control surfaces and throttle for a good landing.
And yes, playing FSX with Xbox controller, landing is where I wish I have throttle or sometimes even rudder controller (since by default the directional control controls nose gear, ailerons, and rudders at the same time)