English, as with any language, reflects the history of its people.
Which in the case of the English, meant Celts conquered by Romans, conquered by Saxons, conquered by Normans (who were themselves descended of resettled Vikings). It's a mongrel language, with all the good and bad that entails.
You forgot the fact that classical Latin and Greek got compounded onto it[1], and at the same time as we exported Empire to a lot of the planet, we imported various loan-words from them.
And the process hasn't stopped, because we're importing not just words but
grammar from the Americas. (My Dad's always talking about "Have you a <foo>?" being replied to by "Yes, I do.", instead of "Yes, I have", IIRC, but then he's a lot older than me[2], and my grammar maybe contaminated by significant post-war 'Americanizations')
Tell me, though, all you English-As-A-Foreign-Language people... Do you see the problem with the phrase "I could of done something"? A lot of native English speakers don't. Drives me
mad.
Tell you what, though, I admire the Acadamie Francais (sans the properly-accented letters, there; sorry, AF!) for their attempts to keep the language pure. I find it ironic, though, that it wasn't they who came up with the term "couriel[le]" as the non-anglophonic alternative to the loan-word variants of "email". An elegant word (similarly compare "l'aerogliser" and "l'hovercraft") that I wish I could use more; but I'm largely non-francophonic, unfortunately.
Anyway, the problems with English, native-English-speaker-who-doesn't-like-it-much, is almost certainly a problem with
any natural language. The most common verbs and sentence constructions were solidified through common usage before more global rules came in. Look at "to be" in its various forms, in most natural languages (possibly excepting some 'reformed' ones, if they've given it a real go at standardisation). "I am", "You are", "He is", "Du bist", "Ich bin", "Je suis", "Il est", "Nous sommes", as just various samples that I think I'm fairly accurate in quoting...
Spelling-reform has been discussed for the last few centuries (but never really caught the public imagination) so unlike some other places, we do tend to have the
odd exceptions.
The "ough" pronunciation being the oft-quoted example.
[1] Sometimes at the same time... "Television".
[2] Obviously, he's older than me, but the point is that he's a
lot older than me. And I'm no spring chicken myself...