Persian ought to be pretty good for crosswords. There are no case endings to make things fiddlier, and the?ezafe, the grammatical particle that holds noun phrases together, is usually not written. Further, the short vowels, at least in the middle of words, are not usually written either, allowing for more possibilities for anagrams.
The vocabulary looks open to borrowings, from Arabic for obvious reasons, but also more recently from French.
Here is an example clue: (???? ???? ?? ??? ?????? (?
Transliteration:?gorbe-e bozorg az shahr Irani (big cat from Iranian city)
The answer is ?????.
Transliteration:?Shiraz
Working: ??? (shir) means “lion”, as in Shere Khan in Jungle Book (or indeed “milk”), and?az means “from”, so if you stick them together you get an Iranian city.