They could use the same system to set defaults for other queues. You load into champ select for ranked and it uses the same positions and default selects the runes, summoners, and champ from the same settings as QuickPlay. (You can still change these based on bans and team comp.). You'd have more people with default selections in champ select, and a better idea of what your teammates are looking to play.
For skins and chromas, it makes sense that it's harder to implement. You want to reuse as much of the existing interface as you can, but most of that is built for champ select screen. Duplicated code is usually bad, but it's not clear if there's another option. Refactoring the chroma/skin selections to use the same code in and out of champ select may be painful, and may not be worth the effort over just duplicating some functionality. It'll just add the permanent maintenance overhead of making sure you update two places when those things change.
For other game modes, especially ranked, they really need to start considering champ select to be part of the actual game. When the enemy team picks five adcs, and your team takes Rammus and Malphite, you've won part of the game. What do you get for that? A dodged champ select, or worse, a "remake" game wasting ten minutes of your time. For people who seem to care so much about 30 extra seconds of queue time, they sure don't care about ten wasted minutes in a remake, especially when the reason is that one team dominated champ select.
At a minimum, the leaver should lose full LP (say, -22), and the winners should split that small amount of LP five ways (+4). The other players losing one or two LP is also reasonable. Champ select is part of the game, and we should start acting like it.