I think there is a middle-majority where things will work out as intended.
I think you're going to be shocked by how small the "work out as intended" group is, because of the combination of the limited stat choice and the forced two skills together with the thematic background.
I think the Feat will probably be less of an issue, oddly enough.
As soon as the full list is out, people will start picking at it, and rightly so. People will see characters they've played for years, or even decades, are flatly illegal under the new rules. Oh your backstory for your Wizard is that you were a Urchin? Well, that background doesn't have INT as an option, so you're going to be permanently dumber than another INT character.
It's just now they are tied to something non-inflammatory.
It's not really non-inflammatory. You've moved from saying to "All elves are more agile but less tough" or the like, to "All street people are tougher but dumber".
This is classic WotC stupidity, and inability to see past the end of their nose. If they'd kept Custom in as a default, they could easily have argued that these were "just examples". But they didn't, so they can't. Instead they've made it so you're inherently less potentially intelligent or less potentially healthy or stronger or whatever based on what, previously, was just a minor choice.
Does that make Background more important? Yes. Will that work out well? I definitely don't think so. Background is a weird thing introduced in 5E, that frankly most PCs (rightly) gloss over in favour of their character's actual, y'know, backstory.
I will state again that personally, I don't see a problem with this. I personally believe that often, choosing the non-optimal branch often leads to other unintended optimizations.
I don't entirely disagree but it's very much beside the point. When that's serendipitous, people are delighted by it. When they're forced into something they don't like, it just annoys them further. Further, both the examples you provide are of (presumably) intentional choices, not being forced into something, which is illustrative of how you're not really seeing what's going on here.
I get that too. I'm just saying, for a large portion of the players, in the end, it won't make a difference during actual play. (It will make a notable difference from a perceived point of view.)
The first bit is questionable and conflicts with your point re "unintended optimizations", but the second, bracketed point is pretty key. It will make a big difference to how people perceive their characters and the 5E 2024 system, and it'll be strongly negative. People are going to feel they have to take themes they really DO NOT want to take, just because that's the only way to get the stats and/or skills their character "needs". I'm sure occasionally that'll have some positive outcome, but a lot more of the time, it'll just piss people off.
And a whole bunch of people will live in blissful ignorance about this, and insist it doesn't happen, because their DM just says yes to every custom background, which probably ends up being most of their backgrounds.
