I don't actually think they made a mistake. I know every CG announcement trailer I see is probably 5 years out, and appreciate a vision of what the devs are aiming for. It could change completely, but it's better than a logo. I will say though that I liked the 12 month window of the last showcase.I actually disagree.
I would actually like the big summer show to keep with the 12 month window, and perhaps have another show around the Game Awards for further out announcements. It doesn't matter though, nothing will ever be good enough for some people.