Really? I've always thought of heteronyms as one of the most stand-out features of English that exemplify its confusing inconsistency. More so than the homophones, because it's harder to think of the "other" meanings if you've got the wrong pronunciation in your head.

In reference to the passage you quoted about diacritics, if only you had read as far as the next-but-one paragraph, you might have noticed: "Words that retain their accents often do so to help indicate pronunciation (e.g. frappé, naïve, soufflé), or to help distinguish them from an unaccented English word (e.g. exposé, résumé, rosé)."