You are correct...there is no "simpler" way of migrating to the AC15 work environment.
I tried to bring in my AC15 custom office work environment template and it didn't work.
It blocks out some of the functionality that AC15 has new.
For example, the "Renovation Filter Options" pull-down menus wont show up if you try to migrate an AC14 work environment...simple as that.
Sorry, you WILL have to recreate the "wheel" as they say....sorry.
...Bobby Hollywood live from...
i>u
Edgewater, FL!
SOFTWARE VERSION:
Archicad 22, Archicad 23
Windows7 -OS, MAC Maverick OS