I'd argue it's a clichéd trope at this point. Maybe in the 1970s it was a fresh idea to allude to WW2, but I'm frankly tired of space Nazis.
Oh? Then why are you watching Star Wars?
If we want to argue that the new trilogy is good art, then it needs be relevant to the context of its time period, which at the moment, really isn't about imperialistic fascist regimes but something closer to cronyism, cynicism, and social unrest.
Oh boy.
I would argue that imperialistic fascism is a relevant topic for today, purely based on how much of it seems to be making a resurgence lately, but that's neither here nor there.
What you are missing, I think, is that both TFA and TLJ are commentaries
on Star Wars as a cultural phenomenon. There's also some other messages in there, about how we need to resist the fascists and their fanboys, how we need to have hope and
make hope even when it seems we can't have any, but the core of TFA and TLJ is about Star Wars. TFA is, very intentionally, a sort of retread of A New Hope: It retells that story with slightly rejiggered roles not just to serve as an entry point for contemporary kids, but also as a nostalgia boost for people like us who saw the original films as kids. Han says, in TFA, "It's real. All of it.", and at that point, he's talking to
you, the middle-aged viewer and is telling you that yes, Star Wars is still magic, can be magic again, even after all that prequel nonsense.
TLJ, in its rejection of several of the oh so important plot hooks TFA set up, is saying "Yes, we can have that magic back, but we shouldn't try to remake the old. Instead, we need to rebuild it, excise the flaws that one George Lucas put into it in the 70s and 90s, and make it matter to us, as we are right now.
The critic from the video "A Critique of Star Wars: The Last Jedi - Part 1" actually makes a good point early on at 7:35 about making a trilogy of film where the bad guys are puny and trying to survive against the good guys. This would be infinitely more relevant to the social discourse of our time. Instead, we get another Deathstar, another not Empire, another desert child protagonist, and another resistance. If we are to judge the new trilogy as art, then it's from an artist who is too afraid to move out from under the shadow of previous artists, recycling overused tropes and unwilling to embrace something new.
I think that a film about how the bad guys are a menace, yes, but an ultimately pathetic and weak one is a good message if we look at current politics around us. Hux is a buffoon, caught up in cosplaying as something intimidating he vaguely remembers from his history lessons. Kylo Ren is a mess of anxiety and parental issues, who has retreated into a power fantasy (urged on by a father figure that is in turns abusive and nurturing; the very image of a really toxic relationship there). We are asked to laugh at Hux and empathize with (but not exactly
forgive or let go) Kylo, and I don't really see what's wrong with that. Neither of these characters are as intimidating or formidable as Tarkin or Vader were, sure,
but that's the point. It's not a flaw in the movies or their writing that these people don't seem as grand as the old villains: That they
aren't on that same level despite making every attempt at it (just like certain tiki-torch wielding idiots aren't on the same level as the people they're emulating, yet still a thing we need to take serious and combat lest they get real power) is their tragedy.
Early on in this thread, Battuta commented that
I liked this film a fair bit (and it left me with a lot to think about) but I have never seen a major pop culture movie where the people who dislike it so clearly, totally do not understand the movie. It's like some sort of forcing function for comprehending stories.
And he's mostly correct: A lot of criticism of this movie is based around a fundamental misunderstanding of what this movie is and what it is intending to do.
Again: TLJ and TFA are movies about Star Wars, about how we've talked about Star Wars over the years and how these films have shaped our expectations and realities. If the prequels as a whole were a deconstruction of the Jedi mythos as set up in the original films (which is a theory that isn't without merit), this new trilogy is shaping up to be a reconstruction of it, an attempt to give Star Wars its mythological qualities back that got lost in all the midichlorians and trade federations and bouncy ball Yodas. As commercial artistic endeavours go, this is much more valid than most other ways I could think of to continue the Star Wars saga.
I would like to come back to an earlier point you made:
If we want to argue that the new trilogy is good art, then it needs be relevant to the context of its time period
No. Good art doesn't need to be relevant in the context of its own, or in fact any, time period. Whether or not it is is a factor in how popular a given work is on release or afterwards, but popularity and goodness aren't exactly related.