I don't think the intentions of these developers is to fool us, it's just that often times things happen. By that I mean hardware plans change, devkits often times don't fully represent what the actual release hardware will be and based off of those changes, decisions have to be made. Heck, even changes in how the software is programmed can change the course of the visuals of a game.
That being said regarding Hell Blade I think the jump in GPU and CPU warrants what Ninja Theory displayed at the game awards. Game artists are getting better and better as more software techniques and new software in general pop up. It's just polygons, maps, and moving some vertices around, it's not that unbelievable. The lighting also does more for these games than most think. I also think Ninja Theory has been working on this for quite some time so I think what we saw is essentially what we'll get.
Once we see what Sony has to show off I think we'll be able to start piecing together the plausibility of how early 9th gen games will look. So, while I do think there will be games that look different than their alpha or beta footage, I do think it's to be expected and not necessarily deceptive marketing. That type of marketing leads you on until you buy it.
Nintendo eventually showed off Breath of the Wild in its true form and let people play it before release. If the game got no pre-release footage and was just Nintendo putting out renders of gameplay that wouldn't be possible on their base hardware then I'd be concerned about their integrity but that obviously wasn't the case.







