[Matchmaking] Quick Thought About a Role Choice

I'll make this brief.

Normally I pay a carry role, or jungle. But lately I'm like, "eh, why don't I let others choose and I can just fill!" So I do, I choose fill. But time and time again, I end up being support. I've never once been any other role when I choose to fill. My question is why? Is that right?

Support is already a choice. If I wanted to support all the time, I would choose it. When I choose to fill, I expect to have a chance at any of the roles. I don't mind support once in a while. But always?

My point is. If fill = support, just remove the option to fill. Otherwise maybe there should be a system in place that makes it so each time you fill, you WILL get a different role than the last time you filled. At random of course. Once you've played each role once, it will start fresh again. You'll never fill the same role twice in a row.

Thoughts?