That's exactly what was done in Redemptionis Sacramentum (numbers 172 to 175). Abuses are indeed categorized. The problem is that too many people think that just because "I don't see a problem with it" that means they're free to move abuses down a few categories, or just to do it anyway. For example, changing the words of the Eucharistic Prayer is defined as "grave matter", yet we all know many priests who freely change those words. Many people would think that it's not such a big deal if the priest changes a few words in the Canon--but the Church says otherwise.
Thanks for that, FrDavid. You're correct, it does make two major distinctions about matters that are grave, specifying the Graviora delicta to the purview of the CDF, and specifying matters effecting the Eucharist (not part of the above) are grave. Everything else, according to 173 has to "be judged." That section also goes on to say all matters should be addressed and corrected.
The value of any document is in how well it is followed. I would ask the question, "How well is this document followed?"
From my perspective, it appropriately puts the very, very serious matters (bogus ordinations and such) in appropriate hands, and I don't see serious issues that are not handled by the CDF. Everything else, though, gets laid in a sort of nebulous category ultimately at the feet of the local Ordinary. The problems come in when people try to get situations they see as abuses addressed.
In that process, there are some that the Bishop sees as matters for the Pastor to solve, while the Pastor views it as a matter that isn't a problem unless the Bishop wishes to pick a bone with him. As a result, some things fall into a sort of do-loop like we see in large bureaucracies, characterized by situations that make fodder for cartoons; you can't get the information from the clerk at window #7 until you fill out the form at window #3, and you can't get the form from window #3 until you get the information from window #7.
That's not a "system" that is conducive to addressing all matters no matter how grave, and ensuring they all get addressed and, if necessary, corrected. Instead, it is an example of "a fine set of laws" that no one, in everyday practice, truly follows. THAT then leads to situations where clergy don't see a problem with altering this or that because no one seems to have a problem with it. And no one has a problem with it because getting it addressed can be like trying to pull a mule. Meanwhile, look at the lovely set of laws we have that covers things like this!
That's what I'm saying could use a little breaking down, a little clarification. Maybe something a bit more clear, like "If the Priest does not say/do this EXACTLY as it is prescribed, it is a ____ matter and should be corrected by (whatever means)." The same could be done for other, more commonly seen abuses. The question that, IMHO, needs to underlie all of this is, who exactly is expected to recognize the abuse when they see it, and what guidance are we giving them to help get it addressed?
As a matter of balance, I'd also not want to have forms in the back of the church to fill out after Mass listing all possible abuses observed. I dislike the idea, honestly, that we go to a priest for our Sacraments, then have to, in some way, be the Priest Police. I wish I knew a better way than we have, but I don't.