RealGM

Overall would the current Nuggets be better, same or worse with Peak Duncan replacing Jokic?

They'd be at the very least slightly worse. Obviously he improves their defense significantly, but the O is just going to suffer so much more greatly by comparison, despite how good Duncan is on that end. They live and die by Jokic; not a knock on Duncan, this team was just built with Jokic in mind

They would be worse--clearly worse. The entire offense is players with clear and exploitable weaknesses but Jokic makes it all work.

Jamal Murray isn't a lead playmaking guard, but he can score and shoot.
MPJ is a terrific shooter but he needs to be fed and set-up, you also don't want the offense running through him.
Aaron Gordon is a worse version of Shawn Marion.
KCP can score on the break, catch and shoot and cuts.

The overall issue here is you can't be a 105 offense 100 defense in today's NBA--it isn't really possible. Murray/MPJ aren't good enough defenders, even with Duncan, to generate a massive advantage defensively like those early 2000's spurs were built on.

This doesn't mean Duncan is worse era-to-era than Jokic, but Jokic is more valuable in today's NBA and specifically with this Nuggets team.

Honestly for this particular Nuggets team, Jokic is the perfect center.

Duncan would make them worse. Doesn't mean he's a worse player than Jokic.

Duncan won a title with a worse cast than this one.