Even if Tsar Nicholas had survived on the throne very doubtful if his son would have been able to keep the monarchy going. Alexi had hemophilia and was a sickly boy. The Bolsheviks would have won in the end and their blood bath would only have been delayed.
Kaiser Wilhelm was nuts but would it have saved us from Hitler if Willie had been left on the throne?
He wasn’t as much nuts as he was an immature jerk!
A lesson that wasn't lost on us after WWII and our decision to keep Emperor Hirohito on the throne. Wise move.