You can paint over it, pop it off, patch and repaint or select a different style for the gables. Here is a source.

http://architecturalfoamsystems.com/6medallions.html

Beverly's idea of a different material for the gables would look great but if you want to keep the diamonds, perhaps you could paint them a complementary color. As for the house numbers, they should be easily visible to emergency responders (ambulance, fire, etc.). I'd leave them where they are but use larger numbers.

Thanks so much for the ideas EP Visualz & Beverly!

Maybe the house numbers could go above the garage door and above the white trim?

I would paint the diamonds the same color as the rest of the house. That way they disappear and people focus on other elements of the house. As for the house numbers, they do look quite crowded where they are. I would relocate them to the right side and update the actual number style. EP Visualz brings up a good point about safety. With that in mind, in addition to the new location of the numbers I would paint your house numbers on your front curb.

Hope this helps!