Hi Herb,
I would say that attitudes vary from player to player. Some players are resentful of having to make their living in a large orchestra when they would rather be playing solo recitals or doing chamber music. Some musicians get tired of doing Mahler over and over. I heard a rumor that the Berlin Phil. asked Simon Rattle to cool it for a certain period. I don't know if that's really true or not. certainly Mahler is more fun for the back row (brass/percussion) than for the more forward rows. I've met string players who like doing little else than Brahms symphonies ad naseum. However, when you reach professional levels, it's a living. If Mahler is big box office, then few musicians are going to complain. Some players are sensitive to the amount of sound coming from the back row, so they hate doing anything that's noisy. On the other hand, I can't imagine a bass trombone player, for example, not loving Mahler symphonies. But harp players may feel very differently.
I've played all of the Mahler symphonies except for #8. Indeed, the tuba parts are great. M6 probably has the greatest tuba part of ANY work. M2 isn't too far behind either. M4 has no tuba or trombones, but I did play bass drum, triangle and tam-tam in M4.