Rok, the Oscar Peterson at the Concertgebouw album is a good one, if you are not familiar with it already. I would definitely second that recommendation.
Frogman definitely answered your orchestral questions very nicely. I would agree with his speculation about #3 having to do with optional passages, or more likely, actual cuts in the music that were NOT specified by the composer. Another even stronger possibility would be repeats designated by the composer that were not observed, thus messing with the form of the work. Many, in fact most conductors often omit some repeats in Classical era symphonies, for example, which would have horrified the composers of these works - Mozart has some hilarious comments on the subjects in his letters. Frankly, I agree with him. In my opinion, it does mess with the intended form and balance of the composition, and I personally believe all of those repeats should be observed, as they were back in the day. When they are not, for instance in the symphonies of Brahms and others in the Romantic era, the audience is literally not hearing some of the notes he wrote that are played only if the repeat is going to be made, but are not played in the continuation. That's maybe not very clear, but hopefully you get the meaning. I think that this is what the reviewers are most likely referring to, and that it has nothing to do with the technical ability of the players, but with the choice of the conductor not to observe a repeat.
Frogman definitely answered your orchestral questions very nicely. I would agree with his speculation about #3 having to do with optional passages, or more likely, actual cuts in the music that were NOT specified by the composer. Another even stronger possibility would be repeats designated by the composer that were not observed, thus messing with the form of the work. Many, in fact most conductors often omit some repeats in Classical era symphonies, for example, which would have horrified the composers of these works - Mozart has some hilarious comments on the subjects in his letters. Frankly, I agree with him. In my opinion, it does mess with the intended form and balance of the composition, and I personally believe all of those repeats should be observed, as they were back in the day. When they are not, for instance in the symphonies of Brahms and others in the Romantic era, the audience is literally not hearing some of the notes he wrote that are played only if the repeat is going to be made, but are not played in the continuation. That's maybe not very clear, but hopefully you get the meaning. I think that this is what the reviewers are most likely referring to, and that it has nothing to do with the technical ability of the players, but with the choice of the conductor not to observe a repeat.