Worst part about the new colors is how little contrast they have with the text. It used to be a high-contrast white on five relatively-bold colors. Easy to read. Now, it's one drab color on another very similar drab color, with no contrast or readability). (mustard yellow on dull yellow, drab dark green on drab medium green, dark rose on light rose, dark purple on medium drab purple, medium drab orange on just-slightly-lighter medium drab orange, drab medium blue on drab light blue, or, oddly enough arguably the most readable of the bunch, medium brown on slightly lighter medium brown)
And to make matters worse--it used to be that if you synched with Google Calendars via CalDav, you got colors on your iPhone which kind of matched the on-computer Google Calendar colors, with white text and decent readability. But they've changed these now too, with the colors not coming nearly as close to those you see on the computer, and with text colored in darker version of the background color (resulting in poor contrast). And all the colors have been so drabbed out that many of them are nearly identical. AAAAARRRRRRGGGGGGGGGHHHHHHHH!!!!!!!!!
It would be nice if Apple would allow you to manually select background colors from their pre-selected palette--but it really wouldn't be going far enough. Either the need to expand their palette to include more options (so people who want high contrast can do so, and those who don't can stick with their new hard-to-read color combos), or they need to allow people to select their own BACKGROUND and TEXT colors for each calendar, so they can design their own contrast level.
With everything else iPhones can do, this really seems to be a simple no-brainer. What gives, Apple???