None of the above.
I get hyped if its a game in a series I love, made by developers I trust.
Call of Duty: Whatever fuckery it is this time.
Don't like the series, or the game, or the devs [No strong feelings one way or the other to devs]. No hype.
Star Wars: Battlefront [III technically]
Love the series, hate the devs. No hype.
Witcher 3.
Love the series. Love the devs. Hype train boarded.
Nothing else will get me hyped, as everything else is just BS. If you want to get me hyped about a game, make a good game. By the time the demo's out its too late - I'm already either playing and enjoying the game, and I'm no longer going to get hyped. Vertical slices are BS and we all know it. Anything less is just useless.
The only exception to this is "Developer pitches" as you've put it, but detailed ones unless they're from a Dev I trust. This means I want explanations of the gameplay mechanics, and how they will work, what the goal is for them to feel like, and how it should all come together. I want a cohesive plan, explained, its intentions explained for when it inevitably fails to match them for whatever, and some assurance that they'll try to fix it if it doesn't match what they intended. Oh, and of course it has to actually be an interesting pitch.