The symphonic nature of the mass cycles of c.1500 presents many obstacles to apprehension, and in turn performance. Indeed, in many cases, modern scholarly editions have only recently been completed, or even begun. Questions of note (via musica ficta or accidentals) remain a commonplace of scholarly journals. Less than fifteen years ago, leading ensembles recorded renditions which a consensus now regards as totally wrong with respect to accidentals and tempo relationships. Although many of us believed we knew better even then, the questions were simply open enough that others could believe differently. Overall tempo still remains somewhat open, as do many questions on accidentals. Ideas on forces and instruments continue to develop. While it is generally believed that this music was written for small choirs of two singers to a part, with three or four in the highest part to compensate for the thinner tone of boys, the question of instrumental doubling has been anything but decided. It was apparently practiced in some places, in some circumstances, and not others. We also know that vocal technique itself was not consistent. The variety apparent on closer inspection is illustrative of developing understanding in general, as applying broad notions across decades of music and hundreds of miles seems increasingly ridiculous.
The image is one of increasing refinement of our ideas, and earlier scholars or performers cannot be blamed for seeing a century of music as more uniform than we do today. They had to begin somewhere, but the consequence was a cyclic shift from one type of broad idea to another. First, it seemed obvious that the symphonic nature of this music demanded huge ensembles and every manner of instrument. Then, it was demonstrated that church polyphony was the domain of vocal soloists in the medieval era. The fifteenth century saw the introduction of part doubling, but groups acquainted with the results for earlier music doubled with voices alone, if they doubled. Now we know that some performances of e.g. Dufay's music in Italy would have included instruments. Nothing is ever simple, and why should it be? This was a richly creative period, one with a great deal of inherent variety. Attempting to continue this trend of refinement, and develop an even better feel for specific music, we find limits imposed on specialization. Support for music scholarship is waning, and so musicologists cannot typically specialize enough to view the output of individual decades & places as distinctive. Some manage to do so, but the situation is worse for performers. Many of the most prominent groups continue to "specialize" in the music of multiple centuries, and inevitably bend it to their own style, rather than the other way around. Amateurs have little choice but to do the same.
This is not to say that performers should not have space to express themselves, but it does mean that seeking a more detailed understanding is difficult. Moreover, the recording industry often lends economic encouragement to haphazard preparation. It is common for prominent groups to sightread a piece onto recording, perhaps with a single rehearsal, and only spend time performing it when they subsequently tour. In the eyes of the buyer, the recording becomes a document for posterity, but it is really a preliminary attempt. The talent of today's singers is undeniable, and I only wish I could sing so fluently. However, the result is often anything but impressive. Renditions tend strongly toward the superficial, remaining completely oblivious to much of the musical logic. Fortunately, some groups do spend an extensive period studying a particular piece, and preparing it, before recording it. The abundance of detail in this music demands such attention, especially for a piece one has never heard. The recording industry is in financial trouble, and I certainly wish it the best, but the basic tension between the idea of recording-as-document & recording-as-promotion needs to be overcome. Magazine reviewers are of little help, as they (analogously) spend their time churning out as many short writeups as possible, usually without spending any time learning the specific music under discussion.
So when I say there are few good performances, I mean it very sincerely. Improvement continues, especially in technical details, and as people put effort into individual preparation, the opportunity to hear their results helps future efforts in turn. So mine is not a pessimistic stance, but a realistic one. The only cause for pessimism might be the attitudes of fans and collectors, who will steadfastly cling to older renditions which have been proven wrong. This is not to say that one must always be right, but if one is unwilling to get to know music with even the correct notes, let alone issues of forces & temperament & tempi, then what is one saying about it? There is no authenticity for its own sake, not really, but there is a question of "critical mass" in understanding before one can sensibly go off on one's own path and ignore scholarship. One cannot personalize an interpretation without first being able to construct a basic one. Fortunately, the performers themselves tend to agree, and regard their earlier attempts as preliminary, rather than as personal visions to which their fans should cling. Beyond these issues, it becomes possible that scholarship has reached something of a limit, and that significant remaining questions are unanswerable in detail. While we are not quite there (in my opinion) for c.1500 music, we are at least very close for pre-1380 music. Moreover, it may be impossible to balance everything we know, and every aesthetic aim, in a single performance.
Few would argue that Beethoven's symphonies can be encapsulated by a single interpretation, and the same is true here. These are works with a rare richness of detail & symbolism, which even if grasped, may be impossible to articulate simultaneously. The inherent melodic logic is frequently obscured in 1990s performances by a concern for vertical sonority. Concords are easy to perceive, more superficial, and hence easy to emphasize. Motivic development requires much closer attention, but where horizontal & vertical concerns balance is not necessarily obvious. This issue relates directly to vocal articulation, as the 1990s preference for inarticulate (even "mumbled") lines makes for seamless chords. Hearing every word clearly was not the goal of this music; that came later. Yet, I strongly believe that distinct articulation of phonemes brings an intended variety of color. Richness of sonority from voices alone can be achieved, and it can aid in capturing the rhythmic intensity of the music. In no sense, as its tie to postmodernism might suggest, is it simply intended to lie there without contour or excitement. This was the celebratory music of its age, and although pious relative to us, the secular songs of the era mix quite closely with it. It was central to people's lives, and that sort of centrality is only rarely attempted today.
Making broad statements on what is necessary for every performance is largely what I am arguing against, so let me stop short on such generalities. However, there is an attitude toward appraisal which must be fully stated. The more one conveys in an interpretation, the more one has accomplished. We are not to the point, as we might be with e.g. Beethoven, where "less is more." We have barely scratched the surface, and a series of perfect chords is not the glory of this music. Its internal logic is so much richer than that, and that richness is anything but fantasy. Balancing small & large elements will always be challenging, but the attempt must be made based on recognition, not ignorance. "More is better" is often a silly idea, but the current state of apprehension demands its application to this music today.