Although a 10-point drop on Verbal certainly
sounds disastrous, it's important to remember that the difference between a perfect 51/51 on Verbal and a 41/51 (94%) is only about 5 questions--so yes, I would agree that all of my GMAT Verbal scores have been within an acceptable margin of error (approximately plus or minus 5 points on each section).
I still believe that the hardest questions have become harder on Verbal over the last 3-5 years, but of course there's no way to prove that, and all of our test-day debriefs are simply anecdotal, subjective experiences.
Here is what I have learned about the scoring of the GMAT Verbal section from studying hundreds of ESRs (Enhanced Score Reports) over the past 5 years:
51 = 0 wrong (99%)
48 = 1 wrong (99%)
47 = 2 wrong (99%)
46 = 3 wrong (99%)
44 = 4 wrong (98%)
42 = 5 wrong (96%)
etc.
I will end with one important caveat: Because there is no ESR for the GMAT Online, there is no way to know for sure whether the above information also applies to the scoring of the the online exam.