OK, Im on PC on the US server mainly myself. . . so our experience could absolutely differ.
I said they could, not that all of them would, or even the majority would.
But, those that do can become good players adding to the community as a whole. Like you mentioned we need more good players. Casual is but a mindset not a skillset … at least in my vocabulary, which could be why we may be speaking past each other on this point. . .
Most of the people talking about bot filled sides are experienced players, not casuals, casuals that I know usually just claim hacking from my experience, and if they are viewing it in that light, then yes they will leave. But again, culture is different, so you may have a different experience which is fine.
I will leave you with this question: What do you feel about getting rid of matchmaking in its entirety and just have a server browser / join random server in BR, where the official standing servers just have varying BR / BR spread restrictions and also allow for team scramble votes (maybe on the vote thing)?