Morrison's writing style tends to be a bit more divisive than their plotting; while it generally works, I think that there's a lot of writers who are more natural hands at getting character voices yet, and that archetypal writing is generally overrated because of how it can be subsumed by more "authentic" character writing.
Personally, I think Batman either *gains* something from more grounded, "less ridiculous" portrayals, or (much more likely) *switches out* some of his "greatness" for a different type of "greatness."
I always thought that the Paul Dini stuff (stronger character work, better mysteries, tighter pacing) going on at the same time as Morrison's run stronger imagination, greater lore expansion) was clearly superior is several ways, for instance, even though I felt that Morrison's story was likewise superior in others - and that Scott Snyder (greater use of tension and horror) would also follow suit, and sort of be an example of a middle ground that wasn't actually a synthesis, but a third option. And generally... Batman and his franchise are one of the few properties that seems to just generally enjoy both fantastic and faux-realistic mish-mashes without the audience feeling like they have to take a side (at least in the comics; the larger media empire still seems pretty cold on combining those aspects.)
Which is where I think the Al Ghul stuff and Damian's conception kind of stands out as being an area where there *is* a sore spot.
I agree with you that the Al Ghuls have kind of been a weird outlier, since I think Ra's and Talia's general premise is still stuck pretty firmly in the Bronze Age - definitely more evolved than the Silver Age, but still myopic, short sighted, and still a little raw. Ra's is a great, high concept villain, and the idea of Talia having a thing with Batman is also a good one... but as you pointed out, it's not developed enough to really make the "beloved" thing work, and Ra's old obsession with trying to recruit Bruce likewise sort of got old. Probably his best appearance since the 80's was in the Tower of Babel storyline because of how well the "steal Batman's plans" idea worked, and he's still seen as replaceable by a surprising number of people who want to adapt that story. I think part of the reason Legacy didn't have much impact was because it illustrated how his main "complexities" (and Talia's) had faded as comics evolved past him.
...But I think he also benefitted significantly from the Batman Begins idea hitting on hw to update his relationship to Bruce correctly - making him Bruce's mentor actually made the old argument over being an heir and having a faux-paternal relationship ring true. I still think that's probably what should be done with future versions of Ra's as well.
In contrast, Morrison sort of moved the opposite way, making the idea of Bruce having heartache over Talia seem laughable as she became more of a Generic Doomsday Villain - executed well, mind you, but still generic. At the same time, though, I would agree that the "Nyssa brainwashed her back to evil" idea sucked as well. The earlier attempt to update her in the 00s pre-Nyssa feels like a smarter take on her in general - emphasizing her agency by just making her quit the game between her father and Bruce, who you could believably see Bruce having a relationship with.
And I think part of the reason Morrison's take remains surprisingly divisive considering how successful the story was is because it feels like there should be some very "mundane" but tense drama over Bruce and her having a kid while becoming mortal enemies - and the "nuance" of Morrison's take is inherently limited.
Talia as "Ra's With Tits" just isn't that compelling in the long run.