I mean it depends on a lot of things. Is Donovan going to fulfill his annual promise to be better defensively? Probably will be marginally better... will at least be motivated to prove something with Rudy gone. Are the parts of KCP, JC, Huerter (or whatever we get) better than Mike, Bogey, etc. Does a new coach provide some switching stuff... Like Sean Sweeney didn't have a major change in personnel on the Mavs and they went from awful to awesome.
I think we go from 11th to maybe 19th or 20th in most situations. Maybe we fall below that. Our number this year is a little wonky because Rudy missed more time than normal. I don't think we are bottom 5 though...
Your point is well taken though.
That other stuff can help for sure....especially the coaching if we have enough pieces. I think the base expectation would be around 25th if you just swapped those players. So if you're talking about "this percent of Gobert", that's what the actual effect is. Maybe you can amount of more of Gobert with better coaching and roster overhaul. But just in a 1:1 comparison between the two players, I'm expecting a top 5 defense versus a bottom 5 defense.
I just don't love "80% of" type comments because no one really knows what that means. I think saying JC is 80% of Don makes sense in some respects, but someone could say the same about Fox and Donovan and I'd also say the same things. There's no real definition of what 80% of a player means. I have no idea what percent of Gobert can be replicated by Capela, but I would expect we drop massively on defense (and a drop on offense too) if everything else stayed the same.