Diminishing returns (to a large extent)... It isn't a few 5-15 minute trailers geared around showing off pretty graphics that will wow people like you and convince you to upgrade. It'll be the eventual demos of games taking advantage of the order of magnitude more compute performance, and seeming endless RAM reserves that these new boxes will have.
E.g. demos of games that show TOTAL destructability of a game world, WITH full fidelity graphics in an open world game. Demo's with things like fluid, soft body, solids and weather simulation that would have been impossible last gen. Demos that display enemy or even NPC AI that is mesmirising by how lifelike the behaviour will be. These are the things that will define next-gen for us... and for me I'm actually glad for that.
It actually pleases me that many folks like yourself aren't so impressed with the graphics side of next-gen, as the quicker devs and publishers discover that they cannot sell a game based on pretty pixels alone in this coming generation, then the focus of game development and marketing will shift to things that actually enhance games that have been sorely neglected up till now