Combat XP gain should be the mainstay of character development in this game, it's the goal Alex has announced time and again. Most of the mechanics emphasize this - guardians at exploration targets, random salvage-pirates, Luddites waiting in hyperspace to eat Your trade-goods, etc. Combat is the fun part of the game, or at least should be. Everything else just gives an economic and logistical backdrop that makes winning or losing relevant. Maybe giving out more XP for different combat goals might make sense - disengaging with few or no losses (calculated by ship- and cargo-value) should give more XP as a passive for industry/trade skills. Or increasing combat XP based on distance to the core worlds, taking into account the logistical limitations of such confrontations.
Hard level cap is a nonsensical idea, always has been, especially in a singleplayer sandbox, but it can be banished with a simple edit of the settings file. It was an experiment of sorts, and might not stand. On that I totally agree, but honestly, the first thing I do when a new version comes out, before launching, is to go into the settings.json and killing it, so I have no experience on how that feels. I keep wondering why those in the community that dislike it seem so heavily inclined to not customize their game to what they'd like to see, as it is intentionally made quite accessible.
With no level cap (or a higher one), the level curve should still rise a little more steeply from a slightly earlier point to make sure choices matter and "filling up" wanted skills is a hard earned bonus gained by playing with Your choices, not a must-have, but that would be a balancing issue late in development, when all skills and their interactions are fully fleshed out.
Finally, there is an alternative experience I could make with another game, (Wayward Terran Frontier) where combat is super-fun and super-useless. Effectively You earn money really fast by doing trade runs that are utterly booooooring, because nobody can catch You and take Your stuff. Then You run around shopping, again, not doing anything interesting. Looting is quite ineffective as an economic basis. (The game has no XP, progress is done via money only.) It's one of the weak points of the design, that the interesting part and progress towards shining in that part are not properly linked. Alex did a hell of a job on SS, making the fun part appear everywhere and making it so it gives You the means of becoming better at it.
In short, I think this is a very conscious design decision and apart from a few blind spots (level cap, not enough XP for special combat situations) it's great.