For gameplay I agree that the shared leveling system is overwhelmingly better. Netoria 1 had a feedback loop for feeding your strongest guys, which resulted in lopsided layouts later on and could leave you in a rough spot if you didn't, say, level a ranged fighter when you get to that one late game level that has mandatory ranged enemies. Or if you didn't prioritize Carwyn, that final level is basically impossible. In 2 I no longer feel that any particular character is in danger of being left behind, although limiting new abilities by currency does make me feel a bit restricted.
As an aside, I also don't completely understand the phrasing of some sections of the game. In particular, I can't tell what the word "level" refers to sometimes. The groping guide says something about gropes per level, and how locking in a path is done by having gropes reach a threshold before or by a certain level, but I can't tell if this refers to player level or mission or what. The missions don't always say Level 2, Level 3, but leveling is only done once every few missions, it raises several levels at once, and there's no way to tell when it'll happen.
Honestly, it sounds like your problem is just the enemies are overtuned for you. Dying less often doesn't make a game more balanced necessarily. Using Carwyn to beat the level alone while you grope with no challenge isn't balance, it's you ignoring the combat to look at the sexy grope pictures. Groping is supposed to be something that has a cost to achieve. You have to intentionally do sub-optimal positioning to make it happen and sometimes that will cause problems in the level. So if the problem mostly boils down to Normal demanding too high an expertise of the skill system and good tactics for most players to not lose units all the time, that's pretty easily addressable.
I thought a big reason netoria 1 felt so good as an NTR fan (and someone with 0 SRPG experience) was
because seemingly simple and optimal gameplay resulted in gropes. There was a clear tank character, and I felt the obviously proper decision was to place all the squishier characters near her to keep them alive. I had a much easier time and cleared levels faster by moving as a group. And then there was the whole set of equipment that gave her massive bonuses in exchange for higher grope rates... Just a perfect little unnecessary double edged sword.
Carwyn alone never felt strong enough to
completely solo a level on normal difficulty, so even if I would have preferred to play like that, I'd still need to keep some other party members leveled up to progress. And if I wanted to prioritize a particular antagonist's path, I had to eschew leveling others safely which made later levels harder as a result.
The NTR didn't feel to me a reward for skilled gameplay, it was a punishment for taking the easy path. I had to work harder and carefully choose my abilities to
prevent groping. There were consequences for taking the easy way out, however tempting it might be. It overturned all the old lazy NTR game writing where the content was decided by either a simple "click here to be NTRd" button or more lazily, "you lose here's a short scene of heroine X getting it. now reload the game like none of this happened".
At least until the dancer class swap, which completely flipped things over again since the tank could no longer provide protection. It always felt weird to me how going down that path resulted in the game becoming 10 times harder, and now I know it's because it was designed under the expectation that I was either playing perfectly and evenly spreading out experience so every character could hold their own or I was neglecting everyone in favor of Carwyn.
And that further explains what felt to me as a large paradigm shift in Netoria 2's gameplay. Now it really does feel like I'm supposed to be trying hard to trigger gropes. There are smaller incentives for placing units near each other and bigger demerits to taking your time. Azar's 'love' path, which involves (for some reason?) keeping Zaman and Shah together is easier because Shah gets a little bit buffed by being next to Zaman. Vash and her NTR route require keeping Shah away from both Zaman and Azar since he'll get debuff, while Vashti gains no bonuses. The turn limit assassins feel especially bad - I felt like shared leveling did enough to communicate "you don't have to kill every enemy", and the assassins just feel like punishment for not playing with the exact perfect setup. Time limits in levels are always stressful, all the moreso when they're as strict as they are here. I don't think I made it through a single level before they showed up.
As for Zaman and Azar, this is another interesting thing to dig into because your takeaway from the game is pretty different from my intentions as the creator. Which to be clear is a problem on me, not you. In terms of gameplay, POV Azar is much closer to Carwyn than POV Zaman is. He even has lone wolf! And in terms of moral code, Zaman is intended to be the more selfish character. Nothing he's doing in the story is for the benefit of anyone except himself. He doesn't want to be king for the benefit of the people or anything, at least not until he runs into Tariq again. And taking the fall for Shah is all a part of his and Vashti's plan which he intentionally is keeping secret from Shah. While Azar is tagging along mostly to help his friends, at least until Vashti proposes he try and seduce Shah.
I'm in this boat too for sure. Azar just struck me as a 'nice guy' incel type upset that his crush chose someone else. Everything he does feels motivated by selfishness, self importance, and moping over losing something that was never his to begin with. He's quite nasty the whole time, even while seducing Shah he's doing the typical "he doesn't care about you, I'm the Nice Guy he'll never be, you'll see how good I am". He follows one of the more overused styles of corruption antagonist/protagonists, right down to being apparently pretty well endowed and sexually talented. I think part of this impression stems from Azar and Zaman's weird friendship, where it's pretty clear Azar hates Zaman, and I have no idea why Zaman likes Azar. I was completely flabbergasted by Zaman's outburst after he cheats on Shah and she leaves him for Azar.
On the other hand, still from the Azar pov, Zaman just seems like kind of a himbo type to me? He's not very smart and doesn't really have any plans or anything, he just wants to be Sultan because he thinks that's what princes do or something. There's no grand ambitions or evil machinations.
It's interesting to see the mindset that went in to some of the decisions that made one of my favorite porn games, especially the contrast to how I perceived Netoria 1 as somebody who does really like proper full-on NTR. I'm the exact opposite of those puritanicals who find NTR in everything, though, because I don't jive with the interpretation that "all sex that your character isn't involved in is NTR". For me it's gotta involve someone that has a strong emotional/romantic attachment to the player character; they have to feel like they're 'your' something, be that wife, girlfriend, childhood friend, stalker, even family member. Carwyn and Gwen had some good chemistry shown right away and were very clearly into each other throughout the whole story. Even the lady that came later was great, though their obsession was mostly one sided at their introduction, her forceful offering of her affections makes losing her feel like actual loss. And conversely, ex-whatevers are
usually excluded from being NTR especially when that connection was severed before the media started.
At least that's my opinion. I know there's a billion interpretations of NTR and that there are a lot of people who assert they love NTR but are
actually fans of corruption/femsub/degradation and don't realize those things can be different or just don't care to know. Those are the sorts of people who'll comment on NTR media and go "I liked it but why didn't MC-kun just do all the sex be cool and strong and make all the girls suck his cox!!" And obviously that's fine nobody's asking anybody to come out here and be introspective scholars of pornography games.