I wouldn't say Veronica made Diana look like an idiot. She did almost immediately and correctly deduce that Veronica was responsible, and resolved to help free Nemesis from her control. She couldn't really take further action in the situation without making herself look worse, and Cale just angrily confronted her with a truth that she could no longer deny, hence her understandable reaction at the end.
One detail in the art I noticed that I liked was Veronica clutching her necklace, which we know has significance to her in the pre-Flashpoint backstory with her mother. I guess we take that as an indication that it's still canon? And I think it enhances her relationship with her own daughter.