It uses the original engine
Minecraft: Story Mode is coming to basically every platform ever, as most Telltale games do, but this one is different — according to an interview from Family Gamer TV it uses the actual Minecraft engine instead of Telltale’s aging visuals. It’s an odd bit of news, since the Wii U has been deprived of the full Minecraft experience for years now. Now that the hard part has been done, some are speculating that this could allow for a full Wii U version.
Of course, Minecraft is now owned by Microsoft, so if it doesn’t deem the platform worthy, nothing is happening. Also, just because the engine is being ported by another developer, it doesn’t mean that Microsoft would necessarily want to pay to produce and distribute the game.