German is easy when compared to Russian. Only four cases in German, six in Russian.
"Difficulty" of a non-native language is best defined by its level of difference from the speaker's native tongue. There is nothing inherently "difficult" about case endings per se; Finns manage with far more of them than any Indo-European language, past or present. But if your native language is English, Dutch, French or another language without this feature, it is "difficult".
English has virtually no case endings and few verb endings, but it has one of the most complicated verb structures of the Indo-European family. No other language I know encodes time, aspect and progressiveness/habit simultaneously and to such depth as English does. Russian has a lot of aspectual nuances but only three actual tenses. Romance has a continuous/imperfect aspect but only in the past. The Scandinavian languages use the full range of tenses (same as English) to a greater degree than, say, German, but with no progressive forms, and so on.
Yet those of us who grew up speaking English don't see anything peculiar in this at all
FWIW, when using Russian case endings (and verb endings for person/tense) don't bother me. Perhaps it's because I learned Latin back in the day. But the nuances of all the prefixes you can add to verbs to subtly alter the conditions in which the action is carried out are sometimes baffling. Perfective vs. imperfective is one thing, but the variation is so much more subtle than that.
