I think it was just the reveal strategy. Illustrating that the "core" was still Halo. Strafe, BR, jumps, etc. It worked, going by how often that .gif was posted. Then they introduced the stuff they layered atop it.
That's certainly part of it, and then the way they were mostly unwilling to detail how any of these systems were going to work in any official capacity didn't help. We saw the core gameplay in March with those Haven clips that always got gif'd, then in the May GameInformer we first heard about random weapon spawns and Promethean Vision, at which point everybody said "oh those are bad ideas guys you shouldn't do that!" That caused Frank and David, the efforts of whom I'm very appreciative of even if it's not going to sound that way, to come in and try and put out fires by saying "oh it's not random, you can't see across entire maps" and those kinds of things (the latter of which is blatantly false in the shipping product). To this day we have not had the inner workings of the Global Ordnance system exposed outside of
this shitty image, which might as well just throw up its arms and and say "it's magic!" for all the use it is. We weren't given any indication that this was the only system that was going to exist, either, or that the options to do it the old way just flat out wouldn't exist or would be totally broken. My favorite example is that in May we were given the details on what the Limited Edition had. Included was a bullet point: "Early access to six specializations!" to which everybody said "Wait, what's a specialization?" 343 clammed up and then finally in August we had the Specialization system revealed to us. Three months to explain a single bullet point that should never have existed without the explanation.
It's a messaging problem and a lack of meaningful dialogue between parties. Not that I think we're entitled to any sort of inside information or anything, but basic explanation of systems would be nice. I've said it before, but Blizzard puts out really excellent blog posts from their designers that directly address questions about how their systems work. I would hope that if 343 is serious about really keeping the hardcore informed, they'd do the same.