You are looking for evidence-based reasoning? I can provide some, though I'm not sure it matters if you bring up the example of Ralph coming off the bench as a freshman, before she is an AA, to Samuelson coming off the bench as a senior and two time AA.
They've played some of their best basketball lately with Samuelson out and ONO in. They've also played some of their best basketball against South Carolina with Walker out and ONO in. They've also played some of their best basketball against Notre Dame with Collier out and ONO in. The common denominator is not Samuelson being out but ONO being in. Given that is the case, if you were to replace ONO for any of the starters you would not do it for the two All-Americans with six games left in their careers.
ONO is not better than any of those three players, but does fit a particular niche better than the other three.
Should ONO start instead of Walker? It depends how correct you are in thinking Walker needs to start to be in the flow of the game. The more you actually think that is true, the less compelling is the reason to start ONO.