Outlaw!

Diplomacy might work, and Izra with Vidomina, of course, but relying on that... Even on HL+, neutral creatures can start joining the opponent in the middle of round 11 and won't stop until they conquer half the map with a Garrison of Order in each of the 7 stacks. It's quite difficult to level up mages; the hope is that one of the 5+ scouts will get a level-up in the early rounds. Although all probabilities are equal at 50%...
What I mean is - you can win against a diplomat, but relying on luck doesn't seem fair for a tournament; experienced players always avoid it, as far as I know. Choosing Luna against Sairah on the L-template is still reasonable.