For me, the biggest problem with fan service is that it's just lazy. And laziness in writing often results in plot repetition and stagnation instead of creative (new) ways to move a plot forward. If that's the point you're making, I obviously agree with you. For example, I'll provide a brief plot description below, and then ask a simple question.
Plot synopsis: The Mandalorian takes baby Yoda with him for safekeeping, but encounters an unexpected attempt to claim the bounty on the baby and/or himself. With some friendly assistance in dealing with the threat, Mando and the baby end up escaping alive and well, but they need to fly off to another planet because this previous one is now too dangerous to stay at.
Question: Is that the plot description for Chapter 3, Chapter 4, or Chapter 5 of this show? The answer is: all three.
Chapter 3 was great, but then chapters 4 and 5 just retreaded the same essential story. Chapter 5, in particular, was nothing but an excuse to use Tatooine for the most blatant uses of fan service that I've ever seen. Take away that fan service, and there'd be zero impact on the story. Worse yet, there's no originality (or point) to the story whatsoever. In an 8-chapter season, an entire 1/8 of it was used for what amounts to very little actual story.
If nostalgia is used to tie things in for plot resolution, or to provide needed context, then it's perfectly fine. But it's just cheap fan service when it's nothing more than "remember this!?" In professional wrestling, there's something called a "cheap pop" to get an unearned crowd reaction. Fan service, in its worst form, is the filmmaking equivalent of that.
Well, don't see it that way.
I see #3 as the pivot - making a choice (and it's a h^ll of a choice really. As a later show mentions, "a bounty hunter gone rogue")
#4 - thinks he did his job (and probably can burrow into some backwater and/or underground in another Mandalorian colony for years, as apparently the Mandalorians will protect their own, but accepts it's worse than that. Not over yet
. Another pivot. He wasn't planning on being a protector long term.
(Also happily introduces Cara Dune, which IMO adds a very nice bit of color in the form of a disenfranchised Rebel. Never seen that before - someone unenthused about this great new world after the revolution and she was on the "right side", yet. (Also there's a hint, maybe, she MIGHT have done something questionable tho maybe desertion is enough).
#5 - firmly entrenched as protector and new life on the run, possibly permanently. Non-guild work, which is a definite step down. Assuming the Mandalorians would even take the child in, both Mando and the child are targets now. (Besides seeing Mando pilot skills tho briefly.)
So IMO #5 leads to some interesting possibilities, and possible scenarios, like, if Mando cares for the Child, would he now go to other Mandalorians for help? I mean, #4 makes it clear the Child was happy outdoors etc. But to the Mandalorians "secrecy is survival".
Don't mind being spoon-fed Mandalorian and journey details 'coz that's been one of my biggest MCU beefs - the LACK of details
. Ordinary scenes like BW tracking down Cap in IW, for instance. At least this kind of show allows for those moments. #4 even managed to slip in "ok, the Mandalorian does eat normally and does take off his helmet". Small stuff but it's part of the world-building and color.
Yeah, fan service but whatever (so far). I prefer NEW planets etc. but winding up in some back alley in Mos Eiesley was alright. At least it wasn't the same hangar that Solo used.
Anyway it might not be laziness so much as Filoni thought fans might enjoy the setting - some did, apparently, some didn't. (Actually didn't bother me as much as another *&&^% bar in ATF - I mean, this was a new "ancient" character Maz Kanata and it's another &^% watering hole with weird stuff - couldn't she have been in a temple or been a beekeeper or something?)
BTW out of all the SW universe only Yoda, the farmers in Mandalorian, and Aunt Beru seem to cook and eat at home. Everyone else spends their time in the street or in pubs.