No tournament should ever have character bans. While this isn't as bad as tournament-wide bans, it still limits variety, and thus limits the strategic options one has in a tournament.
On that note, if a character is overwhelmingly powerful, it should be considered to eratta some of their cards to rebalance things. Similarly, if a certain character just never sees tournament use, there should be consideration for improving them.
A pure "blind pick" would be much better; each player chooses their team in full before the other player knows what they have. If you insist on metagaming, you better study your opponent's past games and see what sort of characters they prefer to pick, and the have to do the same against you.