No he doesn't have the same upside as Rondo.
1) Rondo is more athletic.
2) Rondo is much more intelligent.
Shroder is certainly not a better shooter than Rondo for now. He is maybe a better 3 point shooter depending on how he does with the NBA , but he is awful from the mid range. Rondo shoots one of the best percentages in the NBA from the mid range. It is possible for Schroder to become a better shooter than Rondo, but we will see.
Schroder has Tony Parker IQ in a smaller, less athletic Rondo's body. If he maximizes his physical and mental potential he wouldn't be as good as Rondo. He can still be very good though.
That's a pretty heavy statement. I'm not saying he will ever be even close to Rondo. He may even flame out of the league some day but it's pretty bold to say he has no chance of being on Rondo's level
Not really. There are three things that determine upside.
1. Physical tools. Rondo is stronger, more athletic, and longer than Schroder with the same speed therefore he has more upside physically. Derrick Rose, Russel Westbrook and John Wall (and Lebron) are three top point guards with greater physical upside than Rondo.
2. Mental Tools. Rondo has a far greater IQ than Dennis. Rondo is a thinker while Dennis is much more of a player (similar to Tony Parker). This means Rondo has a greater mental upside as well.
3. Emotional Tools. Drive. Heart. Work Ethic. Spirit. There are many names but it all amounts to the same thing. Does he have the motivation and character to bring out the best in him. Dennis is a very competitive and confident kid, but Rondo is not going to lose to anyone on those factors.
It is certainly possible that Dennis can become a better player than Rondo, but that's because Rondo has not maximized his physical and mental tools. Very few players even come close to that with the usual suspects like KG, Duncan, Lebron, Kobe, Jordan, Magic, Bird etc. coming the closest.
Blake Griffin for example has a phenomenal upside physically and mentally, but falls short in his drive.
Derrick Rose and Russel Westbrook has fantastic athleticism and drive but falls short of a guy like Lebron when it comes to IQ.
Kevin Durant is not lacking in anything but falls slightly short of Lebron both physically (strength) and IQ (play making)
If Rondo was 6'8 280 pounds he would be as dominant as Lebron, if not more. Unfortunately that is an extremely rare combination of size, strength, speed, IQ and drive. This is why Wiggins has so much hype. He has that kind of physical, mental and emotional upside.