Hmm, didn't realize you could "grenade jump" in either game... I guess I just assumed it was a glitch! My mistake.
Perhaps the crawling thing might explain why they removed it, to limit players and prevent them from "exploiting" hard to reach places or getting inside walls like that. Another cheap solution to a problem (like deleting maps that had glitches instead of fixing them).
Hopefully they'll work those issues out and include it again in the full version!