How do I make this banner look better?

I'm starting a nurgle WoC army because I thought it would be cool to make a warriors unit completely out of old hero quest models.
I've finished it but the banner looks terrible. I have no idea how to paint it to make it look better.

Please help, what would you do?

Well, first off, I will say, I remember Hero Quest, so this is quite amusing

However, It's hard to say, because when they're all ranked up it's difficult to get a good sense of the banner and its placement in the unit. Painting-wise, I'd say... um... invert the colors somewhat? Maybe use a darker green for the main banner, and have the Nurgle symbol in a lighter tone. I will say the bits of augments around the banner itself look fine. Other'n that, I'm not really sure if I can help you much more with it.

Good Luck!

If you basically like the colors as they are you could make the logo pop more by painting a thin, lighter version of the same colour in the middle, fading to the base colour at the edge. You could also tie it together more with a series of washes with sepia or mud for a more natural look.

A seraphim sepia wash and that banners good to battle.

Nice to see the heroquest minis get a second life.