The problem with this is, Gortat is a better offensive player than both Gibson and Adams, and Morris stretches the floor more than Adams/Gibson/Kanter do. Not to mention Kanter can be a defensive liability, which is why he only gets limited minutes. Even if it could be argued that Adams/Gibson/Kanter are collectively better, it still doesn't changed the fact that Wall would be operating in a confined space with a lack of perimeter shooters/scorers. Wall's entire game works around being able to find shooters and spacing, his own scoring game works off that. At his core he's a pass first, score second PG. If he doesn't have reliable options to pass to, he'd be forced to change his game/approach and force his shot more while dealing with more defensive attention.
Oladipo is an inconsistent player who needs the ball in his hands to develop rhythm/be effective, who should've ideally been coming off the bench and/or have his minutes adjusted to when Westbrook was off the court. But it never eventuated, because of the lack of wings the Thunder had throughout the season to fill the void. Oladipo isn't an Otto-type player who can provide reliable spot-up shooting, and he isn't a Beal-type player who can provide reliable spot-up shooting and the ability to create his own shot on the regular. He wouldn't have had Oladipo play noticeably better than he did this season, because Wall himself needs the ball in his hands to be effective. You'd basically have Wall/Roberson/Oladipo together trying to provide perimeter shooting/scoring, with two players who aren't particularly effective without the ball and one player who isn't effective with or without the ball, and that's never gonna cut it in today's league.
Like I said above, the fundamental problem is that the Thunder's roster just has too many players that were only effective (some limited at that) on one side of the floor and no players outside of Westbrook who were reliable/talented enough on the offensive end.