People keep saying it should be allowed for casual but not ranked, and that doesn't make sense.
Casual is for, well, the casual fun. It's meant to be no sweating fun experience. Experiment, try other jobs, learn the game, peachy.
But ranked is clearly supposed to be trying to win. The game is designed around coordination and, thanks to the job balance, specific compositions. Why would remove queing with others in ranked? If you want to win, you'd just join a coordinated team and communicate with them.
"But solo queing into ranked and getting destroyed by a premade is so bad"
First off, that's literally already happening. People are queing at the same time and usually getting the same game, with the exception of you can have a throwing friend on the other side now. It's literally only worse this way.
Second off, solo queing with randoms and getting thumb-suckers that don't even know what their own attacks do and getting steam-rolled by the chad perfect composition team that just randomly got given great teammates is any better? Honestly, at least with groups you'd have a chance of not getting a group, whereas now you're guaranteed to get randoms. If you show who's in a party, and maybe give more of that battle pass XP for going against a premade despite not being in one yourself, then it honestly sounds fine.
If you don't want to fight sweatlord stacks just dumpstering your experience, you'd play casual. If you want to win in ranked, and really dig into the competition, you'd just get a team. Heck, there'd be people in PF looking to build a team to que with. If proper communication was allowed alongside party queing, you can really mitigate the experience of getting thrashed by full stacks.

The 'think of the poor newbies' argument falls apart when they have a game mode specifically for them with casual.