i suck at doin the bump, but ive seen some videos of some slick people. i think i probably look exactly like you did.
in videos ive seen tho, that i aspire to, they seem to hit it with exactly the right speed and maintain it.
i think i do the same thing you did, not exactly taking it easy, looks like a little too much throttle that breaks the tires loose at the beginning in combination with a little too much speed and then let off as it hits the bump and that kills the speed.
i dont have enough experience to give the best advice on this, but from what ive seen and felt, looks like you(we) need to stop a little closer to the obstacle. seems like it backed up a bit too far. (that lets you think you can punch it and get goin, that just tends to slip and when it gets traction, theres just a little too much speed) i know theres some timing involved, and whether the tires get off the ground determines if you let off in the middle or if you stay in the gas. either way, concetrate on momentum. if the tires get in the air then you have to have the speed just right and lift off just before the tires go airborne, but get back into it quick enough that the tires dont completely stop when they come back down, but yet not spinning too much either so you dont break anything.
i cant wait to get out there and practice some more

practicing fun stuff is just more fun to have
im still not a fan of taking the back sway bar off, i want to front to do some travel too.
come on experienced rock crawlers, chime in, im more of a two track enthusiast that sometimes has to go over stuff.