I'd like to see Arizona return to a more correct Colorado River outline, as well, but I wouldn't mind seeing something like the simplified Colorado River outline
As for Utah, I like the beehive symbol enough, though the shield could use a bit of a facelift to accommodate 3-digit numbers better, as well as using some amount of color. I don't think that all states need to use state outlines for their shields; in a sense, that makes state route markers follow a relatively boring template, though it would be light years ahead of the circle and square, at least being unique.
What about using symbols from state flags? Alaska does it (Big Dipper), Utah (Beehive), New Mexico (Zia Sun), South Carolina (Palmetto), Washington (Geroge Washington's head), Oregon (spade-shield), and others I can't think of right now.