Let me grumble too.
Encodes actually kill TASing spirit hidden inside watchers.
When people were forced to watch runs on emulator, they had a chance to tinker about, test whatever parts of the run seemed improvable, or just play this new game they didn't know about before seeing the TAS. And when playing the game people find tricks and glitches. They don't find them when watching encodes.
No wonder that majority of recent newcomers aren't TASers (while in the past majority of this forum members tried to tas something).
Encodes just make people more lazy, not more happy or anything. So no need to further encourage this vicious tendency, soon it will prevail anyway. Because encoding is much easier than TASing, so I foresee in 2012 all submissions will naturally have 0day encode as a norm. And TASers will be all the same people.
The majority of newcomers are not TASers because of the age and popularity of TAS videos. It is not because they are not required to play back movies in an emulator.
The majority of newcomers, combined with the age of TASvideos, the high bars most TASed games have, and the relative requirements to get a movie published are the main factors. I have tried making several TASes, but even with knowledge of how the game works internally, I still cannot even get close to some of the TASes that are out there.
Given that many of the more popular games are very, very well TASed, any newcomer who has an interest in those games will be unlikely to attempt it (and any attempts will likely fall, with further discouragement).
As for the encodes... As a lurker, it is easier to open YouTube and watch a video, than play back a movie file. It is also the only way to watch movies when on a mobile device, so if you want to watch a TAS on your phone or tablet while laying in bed, if it is not encoded, you are out of luck.
That said, I agree wholeheartedly with Bisqwit in that such a requirement is a terrible idea. Submissions are already difficult enough; why force the user to seek out an encoder, or worse, encode the video themselves?
TASvideos has encoders and publishers. I would suggest that they work together to provide encodes for new movies as quickly as possible.
As for automating the process... Remember that TASvideos publications usually go on for a long time after the movie file ends, to display the credits and whatever else occurs. There is no easy automated way to track this. While it could be done by having the submission appended with empty frames and then trimmed in the submission process, that would raise the submission bar again (and be subject to all sorts of potential issues).