I think you might be right... I'm definitely open to blue $1's - my Matsui Emerald Bay $1's are blue - and while I think I prefer DG blue as a base in a vacuum (probably the closest I'd ever come to owning a Paris $1), regular blue might work better with the set as a whole.
Something else to keep in mind, all the other base colors in the set have the brass flakes, DG peacock doesn't. Blue, gray, canary, yellow, butterscotch are all weighted. That typically doesn't tweak me (my customs are mixed with weighted/non weighted) but It might be odd to have just one base color in the set that's not weighted. Imperial blue could be another option, it's about halfway between DG peacock and blue.