It was the first translation to use a team of scholars, and the first to use ancient texts.

It was the gold standard of its day

Its really not modern american english as you noted.

I think some people exaggerate the issues with it.

Some things were "left out" because they were not in the oldest texts, which is what they sought to do

The english language has "evolved" since the early 1600s, so that makes it harder to read.

it is a judgement call, but if something is not in the oldest texts translators may leave it out