This topic has been discussed and addressed many times before, but I will briefly explain our stance.
We don't want to bring ELO or ranking play into the game because we don't believe it would benefit the community. Keep in mind that this is a board game first, and it was never designed to be played competitively. That fact alone makes it almost impossible to make balance changes to the game (that happens very often with competitive games). We want to stay true to the tabletop version and provide the same experience (only a bit streamlined with the technology).
However, we've heard the demand for competitive play from many of our players. That is why we implemented the tournament system and cooperated with TTA Pulse to provide you with ways to enjoy this aspect of the game.
A matchmaking system is an idea that seems so good that it raises questions as to why wasn't it ever implemented. This also has some reasons. Considering there are 216 possible combinations of match settings to choose from and an active player base of a few hundred players would make it almost impossible to match up. Not to mention adding an option to chose between ranked and casual play (that would result in 432 combinations).
That all being said, it is also a matter of resources. All of these features would require us to pour a lot of work and resources into maintaining them. For a small team such as ours, that would take our focus away from developing new games -- and that is something we want to do right now 🙂
I hope this brings a bit of insight into our work and plans.