You can guide your clients through their assessment of the creative, checking first whether the messaging is on strategy and then deciding which visual implementation they like best. The most frequent problem our clients encounter is choosing among creative implementations. Don't show any work you wouldn't be willing to produce. If you only have one good comp and four paper tigers, then most likely the strategy isn't clearly defined. If this is the case, go back to step 1.
Good strategy leads naturally to good ideas.
Choose and refine the creative based on the strategy. If you follow this process, the next stage is refining the comps tweaking wording and visual details. You should not have to throw out all the concepts and start over. And you certainly should not have to go back to the drawing board because the message or strategy was wrong. If you work with your client to develop the strategy up front, the presentation should be focused on the visual content of the comps.