Who has the authority to decide if the rubrics of the Mass are to be modified? Since the Pope promulgated this document - which indicates that it is men whose feet are to be washed on Holy Thursday - is it permissable for a bishop to change it?
Since that seems to be the biggest focus of your question, I will repeat what has been said on another thread.
Cardinal O’Malley, who is head of the Archdioces of Boston, sent a dubium (question) to Rome concerning whether or not on Holy Thursday, women’s feet could be washed as part of the service.
Rome’s answer in part was somewhat along the lines of Pilate’s answer of Quod scripsi, scripsi; Rome responded that viri (Men, as opposed to hominem, often translated "men but meaning people) meant what it said; the rubric required that it be men whose feet were washed.
They then went further and said that he should do what he perceived to be pastorally necessary.
A note here; this appears to be essentially a private matter, as the letter has not been published; some have indicated they do no believe it ever occured; that, however is the equivalent of calling the Cardinal a liar, and there is nothing in his history to indcate there is any hint that he is not being perfectly honest. The answer was given publicly by his spokesperson and published in a local newspaper, so he had knowledge the statement had been made public, and he did not retract; further, he washed women’s feet that year (2006).
The essence of this exchange is that 1) Rome writes the law (rubric); 2 Rome means what it says (this one was pretty obvious), and 3) there are issues that Rome does enforce (see, e.g. Redemptionis Sacramentum); there are those issues Rome may enforce or not, if pushed far enough stepping by into a specific issue within a specific diocese, as opposed to a universal correction; and 4) there are issues that Rome simply is not going to enforce, such as this specific issue. They may do so later; or they may not and none of us is particularly accurate in predicting the future.
I prefer not to use the word “abuse” as I feel it is overused bordering on the extreme. Rome clearly sees issues that it feels are necessary to correct, some that it may or may not see that way, and some that it simply sees as not something it will wade in on.
Does the bishop have the authority to change things? In an absolute, literal legal sense, in many if not most liturgical rules, no, he does not.
However, from the very real world, practical sense, Rome clearly sees some sort of hierarchy of rules; that is, they see some as much more important than others. Those that they do not see as important as other rules, they are not going to deal with.
The issue for the Cardinal came up in 2005 when he washed only men’s feet; if caused a firestorm of protest. He wrote to Rome, and Rome both knew the rule, and the circumstances, and decided that he could use his pastoral judgement as to whether the enforcement of the rule was worth the results it would engender.
Many people have problems with that. They also have problems with anything that is not an absolute, complete obedience to the smallest detail. Those people are going to have many problems with liturgical aberrations. I do not suggest that such aberrations are of no importance, but it seems obvious from the above that Rome sees them as of lesser importance than other issues.
In short, if this is going to bother you (washing the feet issue), then you are going to be bothered unless you live in a diocese that is either more in compliance in general with almost all liturgical rules or is heading that direction. If you live in one that takes more of the approach that Rome indicated in this issue, then you will either be bothered greatly, or will need to learn to let go and deal with more critical issues. In short, if the tenor of the diocese is not compliant, the bishop is not going to enforce the issue, and Rome isn’t going to do anything either.
One is reminded of the Serenity Prayer.