Unlikely. His policy positions were similar to Clinton's and its highly unlikely a Republican controlled Congress wouldn't have obstructed him like they did Obama, especially considering Bernie has been ranked as one of the most partisan senators. His approval rating would most likely be where Clinton's would have been, split down party lines with positive views among independents.
You seem to have forgotten the part of Sander's past where he openly sympathized with the USSR and various Latin American Marxist movements.