You know, I don’t think Russian really is all that difficult to learn for English speakers. Arabic, Hebrew, and Chinese are rated as more difficult.
Truly mastering Russian isn’t easy, but that’s because the grammar is complicated (nightmarish?) for people who aren’t used to its complex case or word-ending structure, which is similar to Latin or Greek. But people who have already studied languages like that would probably not find it so challenging.
However, once you get past the different alphabet, which is pretty simple to learn because if its one-to-one sound correspondences, the basic language isn’t all that hard — if you don’t sweat the grammar too much. Most Russian sounds are very easy for English speakers to hear and reproduce, and Russian even has fewer distinct sounds than English. There’s one vowel sound we have a problem with, and the soft consonant sounds are tough for anybody whose native language doesn’t differentiate between soft and hard consonants. But that’s only a problem if you want to try to speak without an accent. In my opinion, hearing Russian is dead easy compared to some European languages like French or Portuguese.
Russian vocabulary isn’t all that tough, because they’ve borrowed a lot of words from more familiar European languages, and because Russian is a cousin language anyway, with many roots English speakers recognize fairly easily after an initial acclimization.
Learning Russian is no walk in the park, but neither is learning any language when you’re an adult. But for us English speakers, many other languages are much more difficult to learn than Russian.
I’d rate Russian a little harder to learn than French or German, but not a lot harder.