In the middle of Gruenwald Cap read right now, forgot how much I love this character.
Classic costume, yes please. Can't believe we don't already have her, but I'd also consider it a boon that we don't: if/ when Hasbro gets around to her, the articulation will be vastly superior to if they had made her even a few years ago.
Definite YES! I really liked her as a partner (professional and romantic) of Cap.
Images 4-5 would be my preference. She should come with swappable heads: pink hair and blonde hair.
I gave up on trying to complete the Serpent Society a while ago, and sold off the members that I did have. That having been said, I'd still like a classic Diamondback in her classic pink costume. I feel she is an important enough character to have even if I don't have any other Serpents.