The Fixer's idea has some merit. Quite a bit, actually. My primary concern here has been the handwavium. So, taking The Fixer's ideas and blending it with what we have already, Greater Rituals are rituals that can be done (but do not need to be done) in the lab over a season and tied to a specific area (without the risk of botch) or cast as standard rituals with all of the risks and requirements that they have under current RAW. I'd also leave it that rituals that are cast as Greater Rituals can be maintained by anyone at a later time, representing the up front time commitment someone put into the ritual, and that they can be easily recast, like a longevity ritual, should they fall, for some reason.
The fact that details of Andorra's Aegis casting are unknown to the ASG[sup]1[/sup] belies Marko's assertion that "[Ritual Magic] ain't broke." Not knowing who is casting the Aegis ignores the issue that it can even be cast, and simply accounts for the vis. Casting it with a tablet, and hand waving that is a huge risk, because obviously, in that situation the spell isn't mastered at all, so it must be cast with a stress die and isn't relaxed. It's broken for the simple fact that no one knows how the Aegis is maintained, and who does it. And this isn't unique to Andorra. The Aegis should be a huge issue for every covenant and it is almost always treated as an accounting exercise. And if you're using a casting tablet for your Aegis, and still treating it as an accounting exercise you are ignoring some pretty huge risks, especially if the Aegis is greater than 35th level, due to the botch mechanics of casting tablets, you're looking at a minimum of 8 warping points from just a single botch. Would you ignore the risks if it happened in the middle of a story, cast any ritual with a casting tablet?
[sup]1[/sup] Marko discussed Andorra's ritual here, which lead to this entire thread. Andorra's Aegis warding effect doesn't need to penetrate, and so requires less of an investment than other sagas that would require an Aegis to penetrate.