ELO scores could be made to matter less.
Here’s one idea. Maybe not a perfect idea, but one I came up with 10 minutes ago on the can.
Have an “Any” queue actually be cycling through an invisible rotation of each game type for 30(ish?) seconds each. The player has no idea where the rotation is, you’re just queuing for anything.
Meanwhile, the game has the entire Any queue trying to match up with one particular game mode (to include people who specifically chose that mode) for 30 seconds, before the whole ANY queue moves on to the next and the next.
Again, this rotation is completely invisible to the player. They could even vary the times to prevent people learning the pattern.
But here’s the key it only groups “Anys” if it can assemble a full team of 5. People who queue for a specific game type can be added one by one to building a group, just like now, but the “Anys” would only pop if a full 5 can be assembled. This can be any combination of specific queuers and any queuers with ELO close enough to group up to 5. If no such groupings can be made, the Anys trundle on to the next mode.
With 30 seconds per mode (and the exact length is still open to debate) the individual queues would only have 1 minute of alone time before the Any mob returned.
If your ELO is so ridiculously high in a particular game mode that even this method excludes that mode … well … bummer?
P.S. GBX, feel free to contact me for my consulting fees