The thing is that they planned and coded everything the way it is for a reason. This is why it's not a design flaw, as these things are all working as intended. A design flaw, for example, is whatever is making the dupe glitch possible, as that is an unintended outcome of a coded event.
Personally, I think the game we received reflects Nintendo's vision of how ACNH should be. If it's dev cycle took 6 more months, the game would still be the same, although probably more polished (the villager related glitches and the duping would probably not be there, as an example).
Nintendo is well known as a company that firmly keeps their policies and ideas despite any kind of backlash from the community. They've been operating like this since they entered the videogame market, even before the Famicom. They're probably not changing their stance now.