I think one of the reasons English is so complicated is that it is so widespread. It's spoken all over the world, so of course it becomes warped in strange ways. But one of the advantages of this is that it's easy to get into an English speaking environment: You can go almost anywhere in the world and find an English book/movie/newspaper whatever. The 'rules' in English are thus easier to pick up.
As Japanese spreads throughout the world, I'm sure this will happen too. Already, you hear 先生たち talking about how words are different in different contexts. (And not just honorific/plain differences)
