This will not put anything to rest, only further a debate that will seemingly never end. There are people who can't accept that we got a mediocre return for a #3 draft pick (understandably so), but looking at it from that perspective alone does not take the many other factors that were at play into consideration.
The only argument that I can see is not signing Booker, but going into the season, even the most optimistic of projections couldn't have foreseen Gobert developing & performing as well as he has this season. Sure there were a few precursors based on his #s last year, but to assume that Gobert would progress into the player that he has been this year would have been unfounded. Theoretically, not signing Booker would have allowed the team to instead carry a bottom of the bench 4th big who wouldn't require any playing time (poor Jeremy Evans), thus allowing the team to play Favors, Kanter, & Gobert each 30+ minutes per game (which may or may not have kept all 3 content).
But heading into the off-season, the Jazz likely assumed they had a starting front court (of the future) consisting of a defensive oriented PF (Favors) & an offensive oriented C (Kanter) with a raw defensive oriented C (Gobert), who had the potential to possibily become a starting caliber player down the road (not this year), so they (understandably) decided to sign a 4th big, with room for growth, who could provide some offense & energy off the bench, as well as solidify a formidable big man rotation to go along with Burke (who was expected to progress rather than regress as he has) backed up by Exum (who, while likely not expected to contribute significantly, appeared capable of handling the back up duties) at PG, & Burks (who I would imagine was expected to take a significant step forward) & Hayward, backed up by Hood (although only a rookie, one who was expected to produce much as he has been- only for an entire year) on the wing.
The FO decided to put a young but talented roster in a position to develop, while still having the opportunity to be competitive had everything gone right (which it clearly didn't, mainly due to injuries & Burke far underperforming his projections). The FO recognized this, so it adapted on the fly (by inserting Exum into the starting rotation & shifting the focus of the season firmly on that of development), much as it did with the way it handled the Kanter situation.
As is with all things in life, you must adapt on the fly. I guarantee that what has unfolded this season is nowhere near what the FO had originally anticipated. Once Gobert emerged as he has, they could have traded Booker to allow for the 3 bigs to get their 30+ minutes, but at that point, it was fairly obvious that Favors & Kanter were not an ideal match, Kanter was unhappy & unlikely to return beyond next year (especially on a reasonable contract), & that Gobert was deserving of a starting role, so the FO elected to go with a future front court that projected to be elite defensively & at least acceptable offensively rather than one that had been mediocre in both regards up to that point.
I agree that Kanter (& Favors to some degree) were handled inadequately by Corbin, but that is not something that a professional should allow to carry over into the next season (& what was essentially a fresh start). The FO made the right decision by adapting to the situation (something that I think has been an issue in the past). Hindsight is 20/20; if only Miss Cleo was our GM, then maybe we would have known exactly how the season was going to play out & we could have gotten full value for Kanter. Personally, I'll take the FO we have & gladly watch as we continue to head in the right direction, even if it means that not every single situation is handled with complete efficiency & that 100% value isn't extracted from every single asset (which has yet to be done by any FO in the history of any sport).