Hi Matroskin,
Welcome to the Forum.
I think you have made some valid points about the fact that these statements are set in the past, and that the writer has the advantage of hindsight.
I still feel, however, that 'there were to be . . ' suggests more that, at that original point in the past, what came later was not foreseen. In other words, to me there is the suggestion that what came later was unexpected, perhaps came as somewhat of a surprise.
If you'll permit me to generalize rashly and be a touch "philosophical", I tend to feel that when there are two ways to say something, there is very often some small, subtle degree of difference between the two.
Best wishes, Clive