I only mention this because it's a visible change that's easy to explain in a few words. The more basic changes are mostly subtle and difficult to describe without direct experience.
> but I don't see anything new than, when programming in Python 2x, makes me think "oh, if only I had used Python 3 here!".
That's not a very sound basis for comparative evaluation. If you have only ever owned a horse, the advantages of owning a car might not be obvious. The horse can go places the car cannot, so the fact that the car gets to other places faster might be overlooked.
That's been addressed -- in Python 3 there are now two kinds of division and two operator symbols:
>>> 100 / 9
11.11111111111111
>>> 100 // 9
11
But you have to remember to use the right symbol. :)I know that I can use __future__ to sort that out, but when I'm writing something quickly, I often forget that until I work out why my code is misbehaving.