@Odola I'm afraid I'm not at all the right person to ask that question. The answer would have to come primarily from Romani peoples themselves (I acknowledge and respect your reasons for eschewing this word, due to its lack of clarity. Unfortunately, it's the only term I know, apart from the "g" word, which in my part of the world is generally understood to be extremely rude, which is why I go to some trouble to avoid it. Such are the imperfect linguistic realities we must navigate). I'm not only not a member of the affected group but, as I affirmed earlier, I'm not even well-versed as an outsider about the state of the conversation within their group about how best to deal with difficult terms like the "g" word (whereas I'm somewhat better plugged in to the state of conversation for other marginalized groups I'm not part of).
Having briefly scanned the plot synopsis, I'm seeing items that make me think there may be other insensitive stereotypes at play - "band of g*p***s" gives me pause - beyond merely troubling wording.
But here's where we come to the other way that I'm unqualified: I have very little interest in opera, and it seems to me that a proper evaluation of how best to handle a cultural artifact like the one you cited would have to account not only for its potential harm to an historically persecuted community, but also its artistic value, and I'm not in an authoritative position to assess either.
You make a fantastic comparison and contrast between the Rangers of Middle-earth and some of the most well known nomadic peoples in Europe. It makes me think there's a lot we could potentially glean by looking at the similarities and dissimilarities in closer detail.
One of the latter, which I wonder if you'll agree with, is that I always got the impression that the Dunedain make their visits to places like Bree individually, or in groups of fewer than half a dozen. I've assumed they never really come close to towns and villages in larger groups, including their children and other non-combatants. Or if they do, they keep themselves so concealed the town- and village-folk never realize their proximity. Does this match your reading of how they tend to operate?
@Flammifer Hmm. That makes me wonder, since the kingdom of Arnor is dissolved, and the line of Isildur in hiding until the last stages of the War of the Ring, what would be to stop some ambitious brigand leader to proclaim himself the rightful heir of Arnor - or just to be a humble vassal of the rightful heir, who must be kept secluded from his memories - and plundering the countryside in the name of the once and future king? Or, worse, what if some ambitious Dunedain were to fall into darkness, sometime after the death of Arathorn, and do the same? Obviously, the other Dunedain or Elrond could prove our hypothetical warlord an impostor, but because of the actual need for secrecy, it would be difficult to convey that to his victims. How would you disprove such a warlord's state authority when the state itself has gone completely underground and is impossible for the common folk to reach or communicate with?