I never used Sora but I recently tried Google Flow and the results are quite good. I have the feeling that Nano Banana 2 has been the image generation champion since it's release so maybe OpenAI feels that they cannot outcompete Google on this task?
And in pure qualitative terms, I'd agree that NB2/NB Pro are still on par with gpt-image-2, but gpt-image-2 is far easier to steer and is significantly better in terms of prompt adherence.