No. First of all, he doesn't have the votes. He has a small, but passionate base. However, they seem to be stuck in a reality distortion field. Trump makes a big deal that the US economy is in a shambles. But US GDP is as high as it's ever been. Unemployment is down to pre-recession levels. Gas is $2.25 per gallon, down from over $4.00 per gallon in the summer of 2008. If things are so terrible, I'm just not seeing it. I guess I don't live in the Fox News Reality Distortion Field.
But I'll play along: Will he be one of the greatest presidents? You mean like Lincoln, Washington, Jefferson, FDR, or Teddy Roosevelt? Come on, really? You're going to put Trump up there with those honored men? Shame on you. This is why the Founding Fathers didn't want people to elect the president directly. They knew that mobs could be stupid and dangerous.
I'll go out on a limb, and say he'd rank 44th if elected. Why not 45th? William Henry Harrison only lasted a month in office. You can't suck more than that.