Hard to argue against these points. They are good ones.
As someone who has utilized various stat generating methods for different campaigns including rolling, point buy, and a stat matrix, I’ll offer a counterpoint by focusing on the point above about disparity.
That is, are we making too big a deal about disparity in stats at the outset?
The goal of 5e is explicitly to have “a good time and [to create] a memorable story.” Do stats, by themselves, or more specifically, the disparity in stats, prevent this goal? In a game of cooperative adventuring, IMO, it’s up to the players and DM to spread the spotlight, which seems to be a much bigger contributor to the goal than a 15% or 20% difference (or whatever one deems a wide disparity) in success at any particular ability check or save or attack. One could argue that the fickle d20 would obscure these differences, when dice are even called for. A DM can also obscure the differences by allowing a reasonable plan to auto-succeed -even if it was from the PC who is significantly worse at that particular skill than any other party member - and very much instead of the DM policing said PC by telling the player “your character wouldn’t think/say/try that”.
I guess I’d also add that a D&D character is defined by way more than their stats. Especially if one does not adhere to the maxim that stats dictate how one should roleplay. If a player feels their character would be fun to play and be able to contribute meaningfully to the parties and thus allow memorable stories to emerge, the disparity problem dissipates.
And, of course, that’s all my approach and my opinion and YMMV.