I have been giving some thought to this recently.
I think "God doesn't care how we..." is a very prevalent but rather glib assumption that is well worth calling into question. People say it all of the time, but I think we should ask: is that true? Why is it so often assumed, without any examination, that an individual of prayer may safely do whatever suits him or her, even at Mass? Where did we get that idea? And why is the person who would question may be automatically assumed to be some kind of control freak? How is that not uncharitable, too?
On what basis can it be asserted that God has no preference about about the care or craftmanship or understanding or unity of purpose or respect for tradition that we put into the Mass, in particular? As NewYorkCatholic's list shows, that the idea does not bear much examination before showing how preposterous it is. I think that every one of us can understand this, because every one of us does something special, something about which we think attention to detail is extremely important. Whether woodworking or sewing or cooking or writing or building or putting on a symphony, we call these "labors of love." Liturgy is labor. Is the Mass not the exemplary labor of love, then, the ultimate "symphony"?
Is it possible that this is the only labor of love for which we may safely ignore the plan or be careless of the details? That seems impossible to me. So why can't we see this one? Maybe we are jealous that others get the work that is done at the drafting table, while most of us only get in when it is time to get out the chisels and lay the stones? Yet how else are cathedrals ever built? Perhaps Mass is simply a greater project, far more demanding of structural soundness, than we give it credit for.
I'm not saying our preferences count for nothing. I'm saying that we should not be too quick to think that our own personal preferences count as much to anyone else, including God, as they do to us, or assume too quickly that indulging our own preferences is always harmless. We need to be doubly circumspect, I think, when we are not, as the clergy ought to be, competent building inspectors. I'm saying that, in the knowledge of our human condition, employment of the axiom that "God doesn't care whether..." requires considerable care, even for clergy.
Our Lord gave the bishops the power to bind and loose that operates both in heaven and on earth. If that doesn't apply to the Mass--for what else do we do that happens both in heaven and on earth as the Mass does?--then I don't know what. So yes, liturgical orthodoxy matters. But I speak of an orthodoxy to the liturgy promulgated by the living Pope and bishops that the Lord gave to us in our time, I am afraid, and not orthodoxy to leaders given to other Catholics in other times and places.