As for when rolling for a Soldiering profession could make sense. . .
For how well someone could perform drill and ceremony maneuvers. From my own time in the Army, I know some Soldiers could barely do D&C, while others could do sharp, snappy, well timed moves that would look impressive. Or it could be for maneuvering through bureaucracy and paperwork, or knowing how to best address and deal with a superior, or how to maneuver armies on a large scale (do we really expect players to know army-scale strategy?) or recognizing rank insignia and symbols/heraldry of other armies.
I like the fiddly bits, the fiddly bits are the heart of the game as far as I'm concerned. D&D has always been about fiddly bits to me, from when I started playing in a 2e game that heavily used the Skills and Powers books to other 2e games that used kits, skills & powers, and a boatload of complex house rules and tables, to 3e and 3.5. A simplified D&D to me isn't a return to anything, it's just. . .D&D Minus.
I'm trying to learn this game, I'm trying to keep an open mind, I've bought the core 3 books and I'm trying to read through them, but this entire rules-light mindset is outright alien to me after 22 years of D&D.
It's absolutely nothing like any D&D I've ever seen before, except maybe the one game of Rules Cyclopedia Basic D&D I played circa 1999. . ..because one guy in our gaming group liked it from when he was a kid and we decided to play a one-shot of it to humor him. . .then the rest of us decided it was way too simple for any long-term campaign or serious gaming and we didn't play it anymore. It honestly reminds me of the rush on here a decade ago towards rules-light retroclones. . .which were a niche thing that some people liked but others found too lacking.