1) No, the only one I could see an argument for would be the escape key, but I'm not fussed about that personally, but I also don't live in Vim. Apps also have custom touchbar functions that are more useful than just the function keys in my opinion (you don't have to learn as many keyboard shortcuts for each app).
2) I don't, other than the customization you can do within macOS. I think the only thing that I've really done is remove the Siri shortcut from it.
3) Good so far. I have a 2018 model which has the silicon membrane under the keys and is supposed to be a bit more resilient. One benefit that this whole mess does have is when my battery deteriorates I can get a new one for free by using the keyboard replacement program. At this point if I didn't already have the MacBook I would wait for the next keyboard design to buy one, but personally have not had issues (yet). As far as the typing experience I find it good for short burst typing and the short key travel is generally fine with me, despite using mechanical keyboards elsewhere.