Frankly, it would tell you very little. Yes, there's a lot to learn but it's not complicated - rote learning because you need to know the rules well enough to not refer to the manual very often as you won't have time when controlling. That's the easy bit. Academically ATC is far from rocket science - a smart Year 9 student would have little trouble comprehending it. There's just a shed load of it.
No amount of reading of notes and bookwork will tell you if you have the aptitude to pull it all together in the manner required to separate aircraft. That's the hard bit that can only be tested in a simulator once you have a sufficient amount of the required knowledge stuffed into your head.