There are no Episodes I-III. Or perhaps better to say, Episodes I-III only exist in my imagination, where they are awesome.
The real problem in this movie is that everyone is doing things their own way and taking matters into their own hands. "My way or the highway" kind of attitude. Holdo is just as guilty of this as Finn and the others -- her self-sacrifice is shown as a noble gesture but ultimately futile. (Which I thought was really cool, to have a movie where the self-sacrifice was useless, even costly!)
Rose is the one who seems to know the "truth". When she says they'll win "not by fighting what we hate, but saving what we love" she captures the essence of the film. "Fighting what we hate" isn't just about Empire and Rebels* killing each other, it's about Finn and Poe struggling against Haldo's way of doing things, Holdo not telling anyone her plan, Luke hiding away because he hates himself, etc.
Meanwhile, Luke's sacrifice at the end works thematically because he is patently NOT doing things his own way. (He didn't even want to get involved.)
I think you're right that it's a subtle take on Self Interest vs. Morality ... it's sort of saying, self-sacrifice is noble and all but isn't a solution that works to further your own way of doing things.
* Yeah, yeah, First Order and Resistance. I'm old school. (First Order just sounds dumb. We know what they are.)