What if instead of removing maps from the pool to make it odd-numbered we add maps instead? This could be done by either Jedi-spamming Muse with a variation of #AdaptTheMaps until they decide to add or adapt a 2v2 deathmatch map, or accepting other gamemodes to play on top of just deathmatch. I would be really interested to see how a KOTH or VIP (not Skyball though - that doesn't seem balanced enough) competitive match would play out compared to a standard DM. Though yes, this would essentially mean Paritan has a higher chance to be picked than any other map, the difference in gameplay between KOTH and DM could be enough to justify the similar map.
Also, back to the topic of map picking itself. Right now this is quite difficult to initially set up, from a referee's perspective. The referee could ask a couple players per team to enter a crew form or lobby with them, or use some third-party client for this. What I would like to see if give the referee, basically the person who sets up the lobby, power to change the maps, or players to potentially vote-change the map. This would help a lot in tournaments in general, not just with a pick/ban.