I work for a SW house where we specialize in projects such as this (as far as I can tell from your description). We have very experienced people, and are well-known in our niche (we are big on Clojure, which gives us a lot of leverage for pulling off difficult projects with a fairly small team). If you're interested in knowing more, I'd be happy to have a chat with you.
Exactly, there's no rationale given, nor any practical example of where this would be useful. Mutability is already a source of complexity, adding time-traveling to it seems like it would just make it worse...
That's a clear case of the Blub paradox, man... Multiple cursors can be useful, but the Vim editing model goes way beyond that. If you're not interested, that's cool, but it's really your loss.
I was having a similar issue with a ca2015 Macbook Pro, new things wouldn't work without updating the OS to whatever the new flavor is. It now happily runs EndeavourOS...
Not only copy/paste, but have notifications shared both ways, use your computer as a phone laptop, use the phone as a trackpad/mouse, and much more. It just works.
It's definitely heavier than Markdown's, but then again, it can do a lot more... In practice, if you're using Emacs, it doesn't really matter, because you can just insert a code block, and specify the language (if you're not using Babel stuff)
The learning curve is not so steep, as long as you don't try to learn ALL OF EMACS upfront. Just start using it for your basic editing, learn how to open/save files, how to navigate, buffer management, as you go. When you need something more specific, you can easily look it up in the great in-built documentation. You can also use something like Doom, which simplifies more advanced setups, and adds to discoverability (press the leader key, and you get a set of options for what else you can do from there).
It's the same with Vim, if you learn how to do basic editing, the rest comes along easily, as you need it. (remember "ESC :q!", though :) )
Tracing debuggers give you the best of both worlds. I've recently started using Flow-storm [0], by @jpmonettas), and it's been quite transformative. You can still easily see the values flowing through your system (better than just "prints"), and it can handle multi-threaded / async scenarios quite nicely. You don't need to manually step through code, you can just "see" your data flow, and when you have loops or some other form of iteration, you can see the data for each pass. Coupling this with a good data visualization tool (such as Portal [1]) really feels like magic. I've been doing Clojure for quite a few years now, and was very happy with my plain REPL-driven workflow, but this is way better.
I wonder what kind of stuff you're working on, that this makes you 4x more productive. For my work (stream processing, analytics, in Clojure), it's useless, AFAICT.
I routinely write in English, Spanish, French, and Finnish, and I code several hours a day. For me, the best layout (other than my Dactyl Manuform's, which is layered) is the standard ANSI US, with a compose key. The compose key gives me easy access to all diacriticals and accents, and I don't need to switch contexts at all.
The layers do take a bit of time to get used to, but they become transparent, after a while. As for punctuation locations, I've exploited that to my advantage, I have brackets and braces (which I use a lot of, for Clojure) just next to my left ring and middle finger, and parenthesis are also trivially reachable, of course. (all this on a Dactyl Manuform, with 46 keys total)
I built a Dactyl Manuform about 2.5 years ago, and it's holding up well, there hasn't been any degradation (even with it shuffling back and forth between office and home daily). I would recommend it to anyone, really. After a couple of weeks of "adaptation time", it's the best keyboard I've ever used for work (I still use a regular keyboard for gaming, when I do game)
I've been using the CAPS LOCK as both Control (on hold) and Escape (tap) for years now, and it's just wonderful. I even kept a similar setup when I built my Dactyl Manuform (one of the large thumb keys is both Control and Escape).
I'm from South America, and have lived in Europe for over 20 years, and I use a US layout, with compose key. It gives trivial access to accents and more, without the annoyance of different layouts (I used AZERTY for years while living in France, and it's just atrocious). I know many people here in Finland who code with a nordic layout, and for the life of me, I don't understand how they remain sane.
I don't particularly like Java (but I did love it back in 98 or so when I came across it, coming from C++), but it's mostly due to the proliferation of OO monstrosities created by architecture astronauts. The language itself is ok, if too verbose. The JVM is awesome when you use something like Clojure on top of it.