Have you checked that you do not have the new "dimming" feature enabled? You can confirm this by holding down a finger on your home screen to go into jiggle mode, selecting "Edit" in the top-right corner, followed by "Customize," and then toggling the option with the Sun icon.
I do not see my home screen wallpaper become dim, but
sometimes rather noticeably desaturated compared to the identical lock screen wallpaper. I hope this is only a bug, given that it seems excessive if you are using the new tinted icons.