I'm able to read a VN without problems (2,5 years self-study, 10.000 individual words learned), but I wouldn't be able to hold a simple conversation, simply because I never practiced it. You can have a near-fluent passive language-ability (reading, hearing), but that doesn't guarantee a sufficient active language-ability (speaking, writing). That's nothing surprising. It's the basic difference between recall and creation. Your course of action should depend on your goal. I never intended to actually speak a lot Japanese, so I focused my study on learning vocabs and a skimming through some grammar. If you just want to read VNs, a good spaced repetition system (Anki), a good grammar guide (imabi.net), exposition to the language (Anime subbed or even jap-subbed) and willpower (continuing to read untranslated even though it's a hassle in the beginning; doing your daily reviews) is all you need. I've never even done a single school-like exercise. --- On a sidenote: I don't recommend Memrise as a SRS anymore. The devs have no clue what they are doing with their site.