Mesmer Duo
It’s fun and rage inducing for your opponents. By all means go for it, we get steamrolled by zergs way too often^^
Play to win. That is all.
Two skilled PU mesmers would be monumentally difficult to kill. However, compared to some of the other duo choices available, it would be overall ineffective. You won’t have a lot of pressure on people, and it’ll be extremely difficult to chase.
My recommendation is generally either roaming with a very glassy thief or a good celery dagger ele. Both provide the chase potential and pressure that you lack, and you provide a lot of good support conditions and allow (particularly the thief) to back off and pick targets without worrying about you dying.