I know what you're saying, but I can also understand why others don't want to perform it . Where I have a problem, is when those same "no sayers" want to dictate to everybody else - prohibiting performances of the complete 10th, in other words. While Mahler wrote at least a melodic line with very basic harmonic accompaniment throughout the 10th, the problem is mainly with the orchestration. In this regard, the first scherzo is particularly a problem. In the first scherzo, no way would Mahler have left the ongoing, chugging motor rhythms up to just strings and horns; who play mostly in their dark, somewhat muddy middle register. Compare what goes on in the first scherzo to just the Rondo-Burlesque from M9, for example. In the Rondo-Burlesque, the ongoing motor rythms are mostly in somewhat arpeggiated lower strings, while the melodic line is constantly fractured and divided up by various combinations of winds and upper strings - both solo and soli. About two-thirds the way through M10/2 (first scherzo), there's a trumpet solo that's suddenly slower. I believe that Mahler would have eventually added a few bars before that solo trumpet's entrance. Listen to how a similar passage happens in the Rondo-Burleque: there's a cymbal crash; some slightly strained block harmonies, and then the contrasting slower section, which is lead by a solo trumpet. The same sort of thing needs to happen in M10/2 to make that passage more convincing. The ending to M10/2 is particularly bad in the standard Cooke version.
The best ending to M10/2, so far, is on the Samale-Mazzuca version. The rapid series of ascending notes should not be played by unison trumpets, as they completely cover over the repeating three-note figures that the horns are playing at a slower tempo (longer notes, in other words). Those rapidly ascending, six-note figures would be less obtrusive when played by some combination of unison upper woodwinds, accompanied by the glockenspiel (and possibly a piccolo too, played an octave higher than the flutes). To also help this ending, it wouldn't hurt to expand the horns from four to six - just as with the fifth symphony (the ending to M5/3 bares some resemblence to the ending of M10/2). It also sounds dumb to have the horns hold that final, long note without anything doing a crescendo underneath. The horns can't do much of a crescendo because they've been playing a full forte already. A sforzando-diminuendo would sound dumb also. I would add a suspended cymbal roll underneath them, just as it sounds at the ending of M7/1.
I've gone into some specifics here. But the point is, there's much in the 10th that sounds uncharacteristic of Mahler, especially in regards to orchestration. Only Mahler could fully finish this work (with the usually ongoing revisions). However, the 10th tells us greatly where Mahler was headed after the 9th, and - more to the point - much about his final year on this third rock from the sun. If only for the melodic line and and basic harmonies, it's still an incredible work.
Barry