During a recent stream, Valorant Game Designer Nicholas Wu Smith said that the game could receive an agent pick-ban system when it has "close to 30" characters. However, then he added that “It also really depends on if we get as much good competition out of banning stuff versus other games.” “Other games ban, but is it actually better?”
If we consider the time that the developer team takes to release a new agent, the ban system won't be discussed for at least three or four years. That's if it's even considered in the future.