(from the OP)There's no doubt our knowledge and understanding of Hebrew and Greek has improved since the days of the KJV.
there's a bit of doubt in my mind about that. I can't say anything about Hebrew, but when it comes to the knowledge of the classical languages in general, I would say it has declined considerably even just within my own lifetime.
Unless you have a broad solid base of learning to draw on in any discipline, - unless it's taught thoroughly and universally to every bright child from an early age,- then the cutting edge of scholarship in that discipline is certain to suffer. The classics aren't like science, with today's results ever superseding yesterday's (if you believe all you read). And I can't believe it's any different with Hebrew, as we move further and further from the milieu that produced the MSS and into an altogether alien culture, with all its antithetical thought-patterns.
If you were to measure today's best academics against those of a few generations ago, such as Burgon, I think they'd come out looking silly, leave alone those 17th Century divines.