Yes, I think that it many respects, Bruckner is a top notch composer. He reaches back to medieval and baroque musical ideas, as well as displaying the strong influence of Schubert and Wagner. But his works aren't virtuoso show pieces for the modern symphony orchestra, except for perhaps the brass. I feel that there are some problems in the way that Bruckner orchestrates. Woodwind lines are often times obscured, particularly the bassoons. To me, it's little wonder that Schalk, Levi, and others, tinkered with his works. The problem is, those folks only made it worse in the long run.
I recently watched the DVD of B5 from St. Florian Cathedral with Welser-Most/Cleveland Orch. Unfortanately, that performance falls flat as a pancake. In his greatly altered edition, Schalk doubles the timpani part at the end of the symphony. To be truthful, it really badly needs that (I don't think that his gratuitous cymbals and triangle hurt any either). Unfortunately, American brass sections just can't play the 5th properly, with perhaps the exception of Chicago. Using just four modern F/Bb double horns, just isn't enough to get the horn parts across during the closing brass chorale passages. If you're going to use those acoustically dead sounding double horns, you need to bring the number up to six or eight. Also, the big 6/4 CC tuba - like the one that the young Japanese tuba player uses in Cleveland - is completely wrong sounding for that tuba part. In the fifth, the tuba is much more like a fourth trombone than a super-bass to the entire orchestra. A smaller tuba with a more driving sound is what's required. At least Cleveland used German rotary valve trumpets, with their longer and wider bell sections; that much they truly got right. In the fifth, Bruckner writes completely independent bassoon parts, and you never hear a single note that they ever play. I don't think it would help to bring the number of bassons up to six or eight either - there's just too much other loud stuff to compete with. Those parts need to be divided up to other instruments that can cut through (the bassoons are often times playing counter rhythms that no one else in the orchestra has)
So, what I'm bringing up here, isn't to say that Bruckner is a poor composer by any means. It's just that the way he orchestrates his music doesn't provide enough clarity and/or coloristic "ear candy" to compete with the likes of Mahler, Stravinsky, Shostakovich, Bartok; and many, many others. For many modern listeners, his music comes off as both repetitive and blustery. That's why I'm fearful that his music will slide down the pantheon a bit. By the way, I really liked the fact that Herbert Blomstedt did a fair amount of Bruckner here in S.F. Unfortunately, his B5 performances fell flat for the same exact reasons. In essence, there just isn't enough "oomph" at the climax of the brass chorale to balance out the length and weight of the previous 65 minutes of music. Mahler could have fixed all that very easily.