I definitely think it'll decrease the tension, seeing that AMC is treating this more like a marketing game than something that should absolutely shake the group (and by extension, the audience) to its core. Casual viewers won't care quite as much, especially once Game of Thrones starts back up, as they would have if the episode would have ended with the full scene, Rick and Negan's parting interaction, maybe someone punching Rick after Negan and the Saviors leave, etc. Not only that, but most hard-core fans will be spoiled by the filming of Season 7 in May, and many casual fans will be spoiled as well thanks to articles written about it, Facebook posts, etc. The scene will not mean as much as soon as everyone who really cares about the show has known who dies for almost 5 months before the first episode of Season 7 airs... and if AMC keeps AMCing, we'll get a handful of episodes about Negan/Dwight's backstories before we end up back where this season left off.
I just hope we get the final bits of that scene in Season 7 and they don't just show who died, then cut to the intro credits, followed by another time-skip with Rick and Co back at Alexandria, however long after this, giving supplies to the Saviors. We'd at least get to see a fan cut of the full scene if we get a version of the events from the comic at some point next season. At this point, I don't even trust AMC to do that right, though.
