I am open to the options contained with the PHB. The choice is mine.
The problem occurs with people having no self-control with rolling. I do hope that the only allow one role on hardman mode (or whatever they are going to call it.).
Well for one it wouldn't make rerolling impossible, you would just restart the game making it more tedious. For second people find enjoyment in a lot of playstyles - power gaming is one of them. That's why I think just having fixed number of stats you can adjust is the least tedious and most fair solution. You won't be god of stats just because you downloaded a mod and you won't be gimped either in case you rolled low. You will still need to adjust your stats and have strengths and weaknesses and make meaningful choices. I think random rolls are fine in tabletop game, where you are creating the story together with GM, but in a video game, it's a bad idea. In video game you have same difficulty curve every time, your GM won't adjust adventure to make it possible for you.