Removing SBMM is not a solution.
Put the choice in the player's hands. Because this is the DEVELOPER'S GAME default all players to SBMM on. Then, allow the players to go in and choose to OPT OUT of it. Explicitly forcing players out who enjoy what SBMM does for them is no different than just imposing your will/want onto all players. Give them the choice; then you'll know if people feel the same way you do, and you can fight against people who don't want SBMM.
It's not logical to assume that SBMM is for ranked play. I avoid ranked like the plague because it brings out the worse in people, but that doesn't mean I don't want SBMM attempting to ensure that my team comp is of similar skill to others. There is NOTHING learned in getting stomped by a wildly superior team. What it does is dishearten players from keeping that game installed. And once people leave a game, they rarely come back; thus, you've lost the potential for all future sales.