I lied, it's still possible.
I just have to ask Badspot what some of the things mean...
For example, BlocklandLauncher runs a copy like this:
E:/Blockland/blockland07/Blockland.exe ptlaaxobimwroe -profilePath "E:\Blockland\blockland07\" -dedicated -map bedroom
I just have to figure out how that's generated so that I can use it myself.