I think the thing that gets in my craw mechanically is that as you point out, a non-standard wizard will always be behind from the start of a campaign to pretty much the end, which few campaigns reach anyway.
This says it all.
People want to min/max, not for the character role, but because they don't want to feel like they're behind. It's not the role playing so much as it's the roll playing.
In my personal experience, when people at an rpg table are mechanically punished for playing out an idea they like, they retreat and withdraw into themselves, but when you allow them to live out the fantasy they wanted and feel like their character is competent while doing so, they relax, open up and the real roleplaying flows out of them naturally.
Have you ever played a campaign feeling the whole time like you're behind? Can you truly say it didn't bother you? I'm not trying to trap you with this question, it's just that you say it's "roll playing rather than role playing" as if those two were entirely disconnected, when I believe they're not. Anything that increases your enjoyment of a character is ultimately good for roleplaying.
They are not disconnected but I have indeed played characters with 14s and 15s in the primary stats and not once did I feel left out because the game is a roleplaying game and I was playing my role. The +2 versus +3 is not going to significantly affect the game in anyway beyond people like to see big numbers(which is what the whole min/maxing thing is about imo); it's a 5% increase. It will not make or break your game despite how some people feel about it.
I disagree with the sentiment that anything that increases your enjoyment of a character is good for roleplaying, because by that logic I would enjoy playing a god character with 20 in all stats and therefore that's good for roleplay; which it is not.
Just to try and be clear you can enjoy something that is bad; meaning you can like min/maxing or this dumb ASI change and it can still be bad. For example I enjoyed ME: Andromeda but there is no way that game is a good game.
To address the question of is min/max good or bad? Generally it is bad for a game to have a hyper-focus on or to cater to min/max or META. There will always be people that will min/max or do the META but no game should specifically do things for the min/max or META.
