I think you're missing the point. A creole language, which English is, after a fashion, is a language that comes about when speakers of different languages come together and come up with something that's intelligible to speakers of both languages(1). It is by its very nature simple. Grammatical complexity is very much reduced and the phonology converges on what is pronouncable by all speakers of the new language (and therefore is reduced in complexity as well.

Now I'll grant you that the differences between Old English and Old French aren't that large, which probably accounts to English being relatively complex for a creole language, but if you compare English grammar and phonology to that of related non-creole languages such as German, Danish or French, you'll find in English they're much, much simpler. Not as simple as in Indonesian/Malay (which jumbles Arabic, Sanskrit and a bunch of Austronesian languages) or Tok Pisin (which jumbles English and a bunch of mutually unrelated Papuan tongues) but at least as Germanic languages go, English is fairly easy to learn.

Of course Esperanto is a jumble as well, but it's a jumble that is entirely artificial. I'd argue that a natural creole such as English or Swahili is superior: it's developed over dozens of years by a large number of speakers of widely differing skill levels whereas Esperanto was thought up by a small number of highly skilled language experts.

I'll agree with you that for native speakers of Indo-European langues (like mine, which isn't English, by the way), Esperanto is easy to learn and use. But my point is it is not easy to learn for people who aren't native speakers of an Indo-European language and that if you're going to make these people learn an Indo-European language anyway, you might as well just make it English.

(1) technically speaking, that's a pidgin, of course. But once the pidgin starts having native speakers, it becomes a creole, so the point still stands

edit: typo