Suggestion for Picking Roles before Queue

As a jungle main, I find that I get my secondary role of top lane more often than I'd like. I have a simple suggestion that I think would be a good idea and don't really see any downsides.

When you select your primary role, why not have the option to select that role again as your secondary role. That way you would be guaranteed to get the role you wanted. The only offset would be that this would probably keep the player in queue a little longer.

Basically you could select a primary and secondary and get a shorter queue, or select 1 role and be guaranteed that role while having to wait a little bit longer. Opinions?