Lyxen
Great Old One
I do not think it is as easy as you claim, Improvising a tactical benefit which balances is a tricky deal especially when elements the character gives up are level dependent and sometimes extraordinarily potent like multi-attacking. For instance going from 3/4 coverage to 1/2 might actually cover the chances to hit factor of a 2x multi (level 5 or 6 for those who have it) but not account for the likely increased damage...
And this is exactly my point, you are still gaming the system, making computations and looking at purely technical benefits based on optimising the damage.
Players who look for fiction/story will care much less about this (and much more about the cool story that they are creating), but still don't want to be completely gimped by their choices, so giving them advantage or another benefit of the kind will be enough to make their story choices relevant (and possibly better) compared to purely technical choices, and therefore incite more technical players to do the same in the future.
This is for 5e anyway, where it's rulings over rules, not 4e where rules were absolutely everything. I don't want to make a catalog of all possible cases and check for the overall balance of new rules, I just want local rulings that look nice and incite players to look for cool fiction/story/description for very specific cases that will probably not ever happen the game over the course of the campaign anyway.
Again, if your preferred style of play is about optimising the technical benefit of the system, it's absolutely fine, but then it's also normal that the fiction is not an objective and cannot be supported by using the system in a purely technical manner.