Change job in instances please!

[Edli]

or people using healer or tank to que, then changing to dps

So what? If they feel like they can clear the dungeon without a tank so be it. As for your other point, nah that's not going to happen. Most of the content people queue up for on df is easy and nobody is going to kick anyone because they don't have multiple classes. In how many df runs have you been where the party kicks the dragoon hoping to get a BLM for speedruns? If that were to happen it can happen all the same right now.