I've possibly missed the bus on this but I'll say it anyway.

As the Dragonborn, you are technically a dragon in human form anyway. Delphine and the remaining Blades are tasked with killing dragons.

There's something wrong here.

I wish there was a dialogue option to tell Delphine at the end of the game, "No. Stop. Your idea is stupid. Stop. No."

I doubt that this is correct. We are born with dragon blood in our veins. But, the way I interpret this, being born with dragon blood is not the same thing as being a dragon, in human form or otherwise.

I look at it from a biology perspective

Delphine is just a load of mammoth [censored].

How can she get through a whirlwind sprint gate.

Why doesn't she ask you to go outside the inn and shout infront of her instead of saying. "I think your not Dragonborn. Lets go fight a Dragon. If you kill it then I believe you." then in her head she's thinking "I know he/she is Dragonborn but I just want to see a Dragon die."

You kill Dragon for "crimes" that should be forgotten. If you don't then [censored] off".