Hi Rok - I'll address the cuts thing first. In reading what you quoted, it is obvious that in the Rabin recording, the cuts are NOT from the soloist, but from the conductor - the passages in question are in the orchestral tuttis, when the soloist isn't even playing. The writer does not know why these cuts were made, and clearly hasn't done any homework in trying to find out - you can take what he said about "no rhyme or reason" with a grain of salt. They may not be particularly good cuts, but obviously they at least work, or they wouldn't/couldn't be made. If they were made specifically for the recording project in question, it almost certainly had to do with the timings of the LP side. That would be my best guess as to why the cuts were made, something this writer obviously didn't even think of (perhaps he is reviewing a remastered recording on CD).
Quite a few people would also argue that one doesn't necessarily need to hear every note Paganini wrote, since he wasn't the greatest composer, but that would be a whole different debate.....clearly every note of the solo part is heard on that recording in question, in any case.
And yes, cuts are made all of the time, especially in operas and ballets, for all of the reasons I listed in my previous post and more. Opera and ballet composers in general expected their works to be cut or rearranged to suit the performers/directors. The idea of the score being sacrosanct did not even exist until the middle of the 19th century at the earliest. In the world of the symphony, really the first composer to make tons of markings in the parts was Mahler, and he was certainly the first to expect that they would all be followed very literally. In the 18th century and earlier, a very great deal was left up to the performer. To give an example from my own instrument - there are absolutely no articulation markings in the solo part of any of the Mozart horn concerti - the performer articulated the part as he saw fit, and any articulations in modern editions of them are editor's markings, not Mozart's. The performer was expected to be consistent in what they were doing, but that sort of thing was generally left up to them. Remember, in that era, the composer was pretty much always a performer writing for themselves, anyway. This is just one of many examples. There are also many other types of musical decisions that are left to the performer, for instance whether or not to repeat certain sections of music in certain musical forms, and there are raging debates on this issue among musicians to this day. That's probably a clumsy sentence, but it is a little complicated to explain. I hope this answers your question, though I realize it probably brings up several others....