If by major changes you mean blowing up the core or trading away a part of the core than I don't necessarily agree.
It all starts with what was going on with the team that caused the team to fall off at the end. If there is a truly detrimental personality amongst the core than absolutely that guy has to go, but if it's things that can be reconciled than we can simply look to reload and get a couple more consistent contributors and make another run.
The only caveat is that we may have only one more legit shot at a run with CP and thus we may need to make a splash move in order to make sure that we have the best chance possible.
But the reality is with CP3 leading the way we really don’t have a shot either