What would you add to Heroes? (creative ideas only!)

The fact that the fifth part of the game places more emphasis on the plot is undeniable, you must agree.

I believe that the emphasis on the plot is just as strong there. It's no less. The plot texts in the expansions for the third game (as well as in the original fourth game) are read like a book. The same is true for the fifth game, but through scripted cutscenes. And no matter how you look at it, the old Might and Magic universe is more extensive than the new one. Although I'm not arguing that the fifth game has a good plot.

it's just interesting why I don't remember them at all, maybe because they are simply not memorable?

In Armageddon's Blade, there is the best "Heroes" plot. I'm talking about the old universe, that is, up to and including the fourth game and Might and Magic IX. The third game has a plot, but the problem is that it is quite complex (if you look at it deeply) and must be considered in conjunction with Might and Magic VI-VII, and with the two previous parts.