Given that Paradise seems to be an also terraformed planet rather than their birth origin one, perhaps their smaller size has to do with the planet gravitational field being stronger. And yeah It's also kind of dumb they are all right there, standing like sitting ducks for the epic LeLz that David is about to release upon them.
I also don't like the contrast of the Giger tech (the big scorpion tail, the derelict-type ships, etc) with that Citadel and them urban constructions. So much Star Trek and Star Wars in the end, instead of making the Jockeys a true Biomechanoid race of some sort, or just a race of nanobots who trascended their biological existance long ago, and conform every single piece of the their tech we see, such as the derelict, the jockey, and the very alien as another piece of their tech. Either of the two alternate approaches would have made the Jockeys justice at least.
Scott has really gone the easy star trek way with the Jockey Retconning. All hope left is these ain't the true Jockeys, which of course sounds like the fool's errand at this point.
