Although they're "unique" I'm not sure that necessarily makes them harder to learn.
Compare Finnish to a language such as Polish with many cases, and Polish always comes out "harder".
I'm biased as I have moved to Finland, and am (slowly) trying to learn the language. It is hard, but at the same time I'm not sure that learning grammar/words would have been easier if it had been related to another language that I also didn't speak!