[aasasd]

A sane alphabet. Cyrillic before the 20th century had some freaky things and weird use of letters that we still have. Aficionados say that ‘ѣ’ and ‘ъ’ could be properly used only by people who memorized all the words with them. (Which is not how modern Slavic languages work, even though English-speakers wouldn't bat an eye at that inconvenience, hur hur.)

[eequah9L]

In Czech, some "y" vs. "i" can't be deduced. Schoolchildren need to drill the words that use "y". Similarly to what "ѣ" had with бѣдный блѣдный бѣлый бѣсъ, except our thing doesn't even rhyme :) (Not that I'm complaining. As you note, English is vastly worse in this regard.)