I think the fact that WotC gave a ¯\(ツ)/¯ when it came to converting old backgrounds says WotC isn't concerned about the balance of backgrounds but wants PCs to think of them as part of their story rather than "free goodstuff"
Then they should not include the "free goodstuff" in the background.
Pick a background, pick 2 or 3 abilities to increase, pick an origin feat, pick a race, pick a class.
Why have 3 of those things lumped together?
. A good reason why customizing them is in the DMG where the DM can kinda monitor them and so that every character doesn't view them as "take the things best for my character" and more "what does my PC's background say about them?"
This makes sense with the proficiencies and arguably the feat, but it does not make sense with ability increases because an ability increase and an ability score are not the same thing. If soldiers are naturally strong due to their profession they should have a floor to their actual score, not a +1 to the 5 they rolled. Making their strength a 6 means they are very weak and if being weak is not consistent with the background then it makes no sense, even though they got a +1.
To me it seems the opposite - WOTC considered making the backgrounds more about the "free goodstuff" than about the story.