There's an interesting conversation going on in the combox of my post on the Filioque, with writers from both traditions making contributions. There is one argument on the Greek side that has me somewhat perplexed, however, and that is the issue of the integrity of the liturgy.
On the one hand, I am fully sympathetic to the idea that the liturgy is one of those elements of our Christian life that really ought not to be messed around with. Lex orandi lex credendi, after all, and the more you muck about with the lex orandi the more likely you are to give the impression that the lex credendi is also up for revision. Impressions are not binding, of course, and this is not the sort of argument that carries any logical weight, but it carries a great deal of rhetorical weight and it seems to have contributed in no small degree to the controversy surrounding the Filioque.
On the other hand, to suggest that the liturgy cannot be changed by the competent Church authority is quite different from suggesting that it should not be, since of course the liturgy is itself a product of the competent Church authority, just as the Scriptures are. In other words, claims about the immutability of the liturgy are very similar to the sola Scriptura principle, in that they are inherently self-defeating. I don't think many serious Orthodox make such a claim in the first place, since all one needs is a good education in order to know that the Eastern liturgies are themselves the product of organic development over time.
The central issue, of course, is one of authority, but not necessarily authority in quite the same sense that underpins the sola Scriptura principle, at least not for everyone. As one commenter has put it, the problem is not so much that the liturgy cannot be changed locally, but that the East resents the imposition by Rome of a standardized form to which all must conform. Indeed, one of the achievements of the Council of Trent was just this sort of standardization of the liturgy, at least for Churches of the Latin rite. Even if we put aside, for the moment, the fact that Uniate Churches continue to use a Creed that is sans Filioque (I suppose that ought to be sine Filioque, but whatever), it is true enough that Rome has sought a certain degree of conformity across the rite ever since Trent. We are beginning to see a contemporary version of this in the West in the form of the imposition of "for many" in the translation of pro multis. However, it seems unreasonable to assume that Rome has any interest in demanding conformity with the rubrics of 1970 everywhere in Christendom--that is not even the case within Roman Catholicism; indeed, it is not even the case within Italy, where plenty of rites more ancient than the Roman one are still in use locally.
As in the case of the debate over the translation of pro multis, which also masquerades as a debate about liturgy, there is a doctrinal element in the debate over the Filioque. I haven't seen any arguments yet that can adequately answer that of Saint Anselm, but I haven't seen all the arguments. The ones that one finds on the internet tend to be rather tendentious--I have looked at several over the last few days to see what is available, and have found most of it rather disappointing, both philosophically and theologically. The place to look, obviously, is in the texts of the great Eastern Fathers and theologians, but many of them wrote either earlier than Saint Anselm or in ignorance of his arguments, so it is difficult to imagine how they might have responded. Speculation can be fun, of course, but it is almost invariably idle in matters such as these.
Until that sound response to Saint Anselm comes along, however, complaints about fiddling around with the liturgy have to be regarded as on a par with other forms of fundamentalism that sometimes operate independently of matters of logic and rationality. There may be a very good and logically compelling reason to think that the Holy Spirit cannot possibly proceed from the Son in any sense, but that reason has yet to be given. (How's that for a tendentious claim?) I remain open to persuasion, obviously, and of course I fully agree that liturgical changes should be slow and organic, nor do I deny that this particular change was not a minor one. But it was a non-ampliative change.