I had a similar suggestion .

1. Change the Join party in progress , to join full run / brand new party . And make it unticked by default , except for first run.

This should increase number of players queuing for parties in progress.

2. Make it so DPS queue invites do not pop up except when at least tank+1 or healer+1 exist in thr group.

3. Random dungeons ( already being implemented in 2.1)

These 3 suggestions will make this a non issue.