I agree. Honestly, I would've preferred to see a color similar to coral if they were going to not include deltas. At least coral is a warm, vibrant, appealing color without being the same as pink.
But with the color staying as is, I really wish it had deltas, because the previous monorails with deltas represent the slightly 'off' colors (lime, coral, teal) whereas the solid ones are basic colors (red, blue, black, gold, silver, etc). Peach fits more in the first category IMO - it's not a color I instantly recognize like red, orange, or yellow (especially given the shade they chose - not the peach I imagined at all).