For example, print and division made more sense to me in 3, judging from friends who taught 2 and said those were always sticky for some students in every class. Intuitive lowers the barrier to entry. (But 2 is probably more intuitive to you because it's second nature to you by now.)
Unicode--when I would test some tiny scripts with Chinese characters or weird ciphers--was pretty easy out of the box in 3.
On systems that only support 2 I find myself slipping in basically a 'from future import all the things.'
These are admittedly mostly cosmetics. But cosmetics matter for noobs like I was, or maybe still am.
I guess 3 also fixed ambiguity in corner cases for error handling? Never came up for me so I don't know much about that one.
You probably just don't have those use cases?
Two people could use distinct subsets of python and neither is using it wrong. Meaning... there could be reasons many of us want 3 that simply don't apply to you. Which sucks, because you get hit with switching costs to help the rest of us.
I think that's the recipe for an endless debate with two reasonable sides.
I will say py2 was already fragmented without 3. PaiMei only ran on... 2.4 maybe? You'd find weird projects that you liked that would then get abandoned. Suddenly you're shimming them all or running four versions. I think 3 woke people up to this as a problem--by making it much harder to patch and way more universal. That made the project more conscious about future and backwards compatibility. Those dividends will only be seen over time. I hope they vest but can't prove how or if they have.
I hope this is helpful... Just know that I'm not saying you're wrong to want to use something that works for you. Switching costs are a real thing, I know it sucks to feel dragged along. But py3 is a lot better for me and others, possibly because we're using the language for different things.
Too look at it a different way... If I see the benefit of & would like to make a change, actually making the change competes with all of my priorities. I'm under the impression that Python is used by many people who use reliable things with APIs that don't change often (I mainly of thinking of Bash & some Posix OS). I can see why they wouldn't be fans of making changes.
Personally I like using newer things, all other things being equal. That's mostly because it's easier to chat about recent stuff with people learning the same lessons I'm learning. Almost every time I ask a C/Bash/*NIX question on a Stack Exchange site, the question gets marked as a duplicate, links to a question with answers I had already, but failed to understand. That happens much less when inquiring on newer topics.
EDIT: More seriously py2's print handles parens in unpredictable ways if you have open questions about types, which has been a nightmare for me on multiple occasions.
I trust you that you never encountered them, but I did.
The whole point of my original post was begging for people to realize their personal experiences aren't universal. The py3 changes solve something for us, help us read code and avoid bugs, it's not just a novelty fetish, I promise. Unfortunately you only have our word for it...