The next update (coming soon) features the option to have multiplayer games use the Warlock Designer. This allows you, much like in the single-player quests mode, to spend a set number of coins each game on the abilities and spells of your Warlock.
Hopefully this will spark some interesting games as players can now use uniquely designed strategies against each other.
Another feature added to multiplayer is 'Warlock Powers' that can be any range from -2 to +4 (where zero is 'normal'). All this does is affect the number of coins allocated to all players, so you can create games with abnormally powerful Warlocks if you choose. Handicaps also affect the coin distribution.
I'll be relying on players to report balancing problems with the new system, as the choices it opens up are so vast it is impossible for me to thoroughly test myself. So please, if certain spells or abilities are causing imbalances by being too cheap or too expensive, or if the handicap system is failing, please make a post about it. I can then tweak the numbers to try and improve it.