Of course they will eventually move to 1080p when it makes sense from many perspectives. The ATV2 is in many ways a accessory to an iDevice. So you need AirPlay working properly at 1080p. I don't see that happening anytime soon. You also need 1080p content from the iTunes store which is apparently in the works.
The ATV2 does not exist in a vacuum. It is part of a digital media wireless solution. From that perspective 1080p is just not a priority.
You might be waiting a year for what you are after. All I can say is that an iPad2 and an ATV2 is really spectacular in the way screen mirroring works over AirPlay. Anything you can show on the iPad appears on your TV. That is no small feat. Apple is not going to change the ATV2 just to compete with the dedicated media players and the reason is because it is not a general media player.
If playing back local content is what you want from a media player than there are plenty of great players to choose from. There is only one that works seamlessly with iDevices. Decide what you want.
If I had a lot of 1080p mkv's I wouldn't think twice about an ATV2. For that matter if playing back mkv files is your thing look elsewhere. How many times do we keep having to say the same thing!? I love my ATV2's, but I am also aware that they are not very good general media players.