It's only a Blu-ray extra. Give it a break, right? I'm just not sure the world is a better place with this new footage of Christopher Lloyd adequately reprising his most famous character in a weak fan service script. I preferred to think of Doc settling down and enjoying his steampunk retirement.
Back to the Future's appeal didn't lie entirely in its retro "predictions" of what 2015 would be like, though you'd be forgiven for thinking so with all the clickbait articles around last year. This desperate attempt to fix that non-existent "plot hole" is just embarrassing. Fortunately, it's only a Blu-ray extra.
"Great Scott" etc. - Emmett L. "Doc" Brown