This is the main issue here and really annoying. I hope they fix it because being stuck there staring at a question mark while everyone else locks in characters sucks.
I like the current system , it encourages you to learn other battleborn if you want to be effective in a match. I also wouldn’t mind this idea though , seems fair enough imho. Evolve had something similar but you could actually set your 2nd through 5th character preferences as well.