No, since content updates (like new blocks, new items, new mobs etc.) are not the only thing added. Even if Minecraft is finished, there can always be new stuff implemented, like better rendering, shaders, better shadows, model makers, camera movement, keybinds, scene creators, better lighting, Ambient Occlusion, Adjustable render sizes, better performance, bugfixing, support for exporting to other programs, better implementation in Minecraft (like importing entities), the list goes on.
Dav stated he wants to have Mine-imator up there with other rendering programs people use, and that will be a heck of a task to finish.