A new patch dropped today. Relatively minor changes so it would seem, but definitely an explanation of why it took so long - apparently they totally rewrote the terrain modification system. Still functions basically the same from our perspective as players, but should make it run better overall. Actually pretty stoked they took the time to do that, since a lot of games at this stage in development just kinda ignore things like that and get stuck down the line with unfixable problems because they've got too much stuff relying on the old system.
I'm bouncing around to see if I note any specific differences. At this moment though, I can just say that the stone cost to raise terrain has been lowered to 2 - land-bridgers, rejoice!
EDIT:
After reading some commentary, maybe don't rejoice quite yet. Sounds like perhaps the ground doesn't raise as much per click as it used to.
Patch notes: