Agree completely with the addition that the 3rd needs to be available from the first match of the season so we don't end up playing West Brom, Newcastle, or the like in our white or navy when they have stripes that are so similar in color.Said it a bazillion times before.
Home: Keep the home-shirt classic & simple.... Subtle tweaks each year (Collar, sleeves trim etc.) mean peeps will still buy. Blue shorts for domestic / White shorts for europe.
Away: Same design format as above in dark blue (never been fond of the sky blue... Especially now we're in the City/Oil-era). Always blue shorts (white always looks shit).
3rd: Get funky with the 3rd kit for those who seek that kind of vibe. Should also be a departure from white & dark-blue.
Honestly, they get it right, I'd buy all 3... Most seasons I typically can't even find one I like.