Alternative (comment below)
Sure, it would be a disaster, but as long as it's optional, I don't mind. Don't forget the consequences though, for those who opt in: -You'll get trolls that join because they enjoy griefing others whom you can't kick. -You'll get people who don't have a mic, refuse to communicate, or are rude/toxic in chat whom you can't kick. -You'll get get underleveled, or just really bad people whom you can't kick. -People wouldn't be as hesitant to quit in the middle since it's matchmade, replacing them would also be a problem unless people don't mind getting dropped willy nilly in the middle of siege engine or something. -Raids last longer than strikes, so people won't be queuing up as often. Not to mention splitting matchmaking by checkpoint would thin out the player pool even more. A lot more, plus don't forget that newer raids now are much more punishing of mistakes. Sometimes a single death or error from a certain role means a wipe. Also, if there is a vote-kick system, it would be abused.