I think English is one of the easiest languages to learn up to a certain level, which is pretty low...my guess would be First Certificate. Then it becomes as complicated as any other rich language. And yessss, English certainly is! one of richest languages.
That's the reason why you can easily detect who is a well educated and well spoken person, because their vocabulary is very wide. It did happen to me so many times when I tried to speak to an English with a working class upbringing, that I, as a foreigner, had to down-grade!