@simplex
1) Both RoadShow and the new Intuition have been developed on 68k.
(RoadShow is even planned to be available this way)
2) ExecSG is supposed to be API-compatible with Exec.
3) Even "nearly finished" is still unfinished.
4) Since Petunia doesn't run on ExecSG (yet) it would be
impossible to use any 68k-code on it, and if Hyperion could
do that, well than OS4 would be finished ;-)