Choosing what to display on this list is indeed a bit delicate. If we want to be fair we should list all Ages, but the UAM list already does that. And many (the majority?) of the released Ages are essentially abandonned or were merely test works.. I agree listing only 'recent and active' Ages is a good start as we can set specific metrics for those, to avoid subjective selections.
Also, wouldn't it be better if the Ages descriptions were not filled by us (as in 'the people doing the site') but rather either by the authors themselves, or by one of the oter Guilds (Archivists and/or Maintainters) ? It would make for a nice collective work and a good occasion to foster Guild interactions...