This is actually a really good idea.
It'll make position swapping extremely common in high elo so much so a new norm may be set and pressured upon. But in the hands of cooperative players it's fine. And it roots out the randomness of pick order & roles of the current draft system.
It completely removes the risks of champion swapping.
But it would mean more activity and complexity in champion select on a regular basis. Then again, it can be ignored and it's not a major factor on the game. People will just overreact. Personally I'm fine with letting people be people if the system itself is better. But that's just me. I'm still bias towards non role select draft because I learned to round out my play in all positions over the years.. That would benefit me most..
IDK about others but I actually get bothered how the positions of players in draft is random when playing ranked premade 3v3 or premade 5v5. Why can't we control that in the lobby. Why is it randomed? This actually affects me because I'm the flex pick on my teams while my teammates are more focused on particular champions. I need to be the one that goes "Oh they're playing adc/supp top (3v3) (PICKS waveclear)", or "oh they're realyl squishy and short ranged (picks Kennen)", or "Oh that champion is reliant on landing skillshots (picks Fizz)"