Worth one visit, and best as a timed one: arrive late afternoon for daylight, eat nearby, come back after dark. A half-day here is more than the canal repays.
Shibuya PARCO gathers Nintendo, Pokémon and several anime brands on one floor. When that is worth a dedicated stop, and when Akihabara serves you better.
Sanrio Puroland rewards adults who want time inside the Sanrio world rather than rides. Whether it justifies the trip out of central Tokyo, and how long to allow.
Gundam Base Tokyo earns the trip to Odaiba for exclusive Gunpla and the large-scale displays. For general Gunpla stock, Akihabara is the shorter journey.