Most nobles in the German Empire also viewed him as an arrogant fool who was plotting to expand his own powers at their expanse.
Very true and even worse for Frederick is the lack of respect he enjoyed among the German princes none of whom cared for his wife's ideas. Doubt if the Reich would have survived long with him on the throne
Well his death was imminent when he gets the throne so he doesn't take any initiatives
Wouldn't be too sure about the survival of the Reich- many of his ideas are anathema to the Princes
What do they propose to replace the Reich with ?
"End of the Reich" seems to be a quite extreme reaction to unpopularity of the reigning Kaiser. Ending the Reich means either ending the monarchical system, or secession of states, themselves monarchical, from the Prussian-led imperial institutions.
Republicanism does not seem to be a solution that German conservatives would approve of, and German radical liberals and socialists who would find republicanism least objectionable in principle, would have fewer problems with Frederick than conservatives.
Since you implied the princes are in the lead of the opposition, so this would logically imply secessions of constituent territories from Prussian control.
If so, which states would be likely to lead the secession, how many would secede, how would post-secession governments fare, and what stops Frederick and other Prussians from suppressing secession? (Who knows, maybe Frederick personally would prefer accepting secessions as a fait accompli to the alternative of suppressing them by force?)
It seems to me that a military/bureaucratic/parliamentary conservative coup to replace the Kaiser with his son, or a prolonged stalemate while anti-Frederick forces footdrag and wait him out, is far likelier than the end of the Reich itself.