[notahacker]

Not just the non-native speakers, but also multiple strands of native speakers (and big regional differences even within native-speaking country, and significant grammar and word choice variation as well as pronunciation differences), no official "correct" version and a certain amount of cultural resentment even within Britain to RP which was intended to be an official version.

And of course English is a very irregular language, with stuff like articles being irrelevant to the vast majority of sentences, and some of the complexities like conjugations conveying very little meaning (as you say, verbs often don't change during tenses; think there are more irregularities with common words than actual shades of meaning conveyed by conjugating them), and many of the common "corrections" like objections to split infinitives actually being based on misconceptions

Actually, I think the prevalence of ESL speakers will eventually result in "standard" English variants on native-speaking TV losing quirks like nonstandard pluralisation and even articles, and it'll be much the better for it.