Okay, according to some research I did, the reason that the displacements don't work is because mods have to update their code to reflect the new sdk and steamappid 215. Something else to do with old dll's and....
You know what... I know almost nothing about coding. What I do know is a temporary fix that can help get you back in the map business.
Hit the compile button, go into advanced, in the $bsp_exe parameters, add "-novirtualmesh" without the quotes to the beginning of the line, and make sure there is a space after it so it looks something like: "-novirtualmesh -game $blahblahblah"
Made my displacements solid, with no ill-effects that I care about. I would conjecture that it probably affects those new displacement options, but since I don't use them in my maps yet, it won't be a problem until I do.
Hope that helps some of you!