The capability to Fill is a wasted skill in ranked

In the old days, it was a huge deal to be able to play every role at least decently because you could be forced into any role any game. Right now, with the new champion select, people can pick their 2 favourite roles, which is great and all, but the capability to be flexible in champion select and fill out any role without performing poorly is now useless in ranked. Why would you pick fill if you can just pick your 2 most confident roles? You have a shorter queue time, but it will only have a negative impact on your winrate and winrate is the only thing that matters in ranked.

I don't have the stats, but I can only conclude that fill must have a below 50% winrate (unless there's a covariate like more very confident people/smurfs picking fill). You can't be as good at 5 roles as you are in your top 2. It's also harder to improve when you have to divide your focus on 5 roles rather than 2. I feel like filling players should get a slightly higher tier than their MMR would represent because being at 2000 MMR with FIVE roles means that you're more skilled than someone at 2000 MMR at 2 roles. Back in the days this wasn't true because the one with 2 roles would sometimes lose games because he was forced into a bad role.

Making fill more popular this way also improves matchmaking because the less popular role will be easier found. More fill also means that a smaller percentile of the filling players will get the less popular role, making fill an even more attractive option.