Eh, I think it's kinda split, but I think the people who are upset had this whole attitude that, hey, the writers kinda shot themselves in the foot and that they might as well screw the classmates and go all-in with Ash for the rest of the series because there's allegedly so little time left.
Well at least nice to know that there are overall and contrasting and divided opinions regarding this matter, and majority of the fans here aren't at least acting salty and pissed off that Ash hasn't caught Eevee, or that Lana has basically stole Eevee.
Also, I know a lot of people are under the assumption that Nagisa won't get any screentime because Lana is so inactive, but that is something I disagree with.
Of course it's gonna get some screentime and spotlight because of the LGPE promo factor and it's screenhogging like playful and comedic personality which is pretty much obvious, but being a Lana Pokemon is way different than being an Ash Pokemon. Ash and Lana aren't even comparable even in the slightest in terms of importance, Ash is the main face of the show as a whole, the protagonist of the show who basically appears in every canonical episode and movie of the show, while Lana is a member of the SM main cast, who isn't even the second most important character of the show. Lana naturally doesn't get nearly as much focus episodes as Ash. Sure Eevee still would get a good amount of focus under Lana, but it isn't even comparable to the focus it presumably would have gotten if it went to Ash; if Ash got Eevee, due to being a Pokemon belonging to the main protagonist along with the side factors of the LGPE promo and its screenhogging like personality, it obviously would have gotten a huge amount if screentime and focus (maybe even lasting even for say, 2 months). Going to Lana at least means that it's focus and spotlight is at least gonna be limited to a certain extent.
Nagisa isn't comparable to Piplup, Oshawott, or Chespin, and honestly, I wouldn't be surprised if Lana and Popplio start getting more screentime because of Nagisa. I mean, this isn't even comparable to Marowak and Charjabug.
Except Nagisa is comparable to Piplup and Oshawott in terms of personality as we have seen seem so far. It is cute and comical Pokemon in that mould, which has a sort of really comedic and playful personality and acts overly cute, playful, and comedic while interacting with other Pokemon/humans, whether it's playfully tackling other Pokemon, whether it's about the overly comedic reactions while it's being chased by another Pokemon being frightened or going through lots of slapstick (which it actually quite often does) in fact. And in the process hogs quite some screentime.
Eevee is basically a secondary mascot at this point, there's no way it's just going to be stuck in the background for the entirety of the series.
Of course, as I said before, Eevee is of course going to get get a good amount of spotlight and focus, but that isn't even comparable in the slightest to the focus it would have quite likely gotten if Ash caught it. Comparatively, Eevee's focus would be at least limited to an extent, because Lana afterall isn't that much important of a character like Ash, nowhere even close.
I
am maybe, maybe, a little concerned Nagisa will overshadow Popplio for the sake of marketability, kind of like how Marowak has kind of overshadowed Turtonator, but given Popplio is an actual Water type and Nagisa is not, I doubt that will happen. Plus there's merchandise that's heavily suggesting Popplio is going to evolve, so it is all but guaranteed at least one more focus episode, at least.
We, Nagisa is gonna overshadow Popplio to a certain extent of course since it's an LGPE mascot, but then again Popplio doesn't usually get that much focus episodes in the first place (I don't remember any except for the Totem Wishiwashi Grand Trial and the sea-folks episode where Brionne appeared) so it's not like that would make a lot of difference. As long as Popplio gets to evolve into Brionne (which would mean a bit of focus at least like you said), I'm fine with it.
As for Ash's team, I'm predicting Poipole and Charizard for now, but we'll see. Poipole I'm confident in. Charizard is more of a bold prediction.
Poipole coming back is fine with me but then again it barely knows how to battle, so it would need sort of a rushed/DEM evolution during a League battle, which would be a bit of cop-out. But Ash at this point hardly even has too many options so its fine.
As for Charizard....I have been telling this for a long time in this thread that Ash's Kanto mons coming in as reserves at the tine of the Alola League would be a lot more convenient than shoving down two rushed captures in Ash's team at this point which would feel at bit out of space. As long as they can distribute the battles/battle focus in the Alola League amongst Ash's Alola mons and the Kanto reserves, like how similarly they did in the Sinnoh League, I think it'd work pretty well.
As I said in the SM99 episode thread, "drama queen" is not the right phrase to describe Nagisa. A drama queen is someone who overreacts to situations or reacts in a melodramatic way (and I don't mean purely for the sake of comedy). Nagisa may be easily excitable and a little rambunctious, but it's far from being a drama queen. As you said yourself, it's cute and comedic. It's not melodramatic.
And I already did reply to this point of yours in the SM99 episode review thread so I will just basically have to repeat it here:
Nagisa actually does act quite a bit overdramatically playful, cute and comical all the time, you can just notice just by seeing its interactions with other Pokemon and humans, whether its playfully tackling other Pokemon, acting hurt in a comedic manner while it goes through a ton of slapstick stuff or whether it's its frightened reaction when it's running away being frightened by a Pokemon. It does act comedically/playfully overdramatic all the time, and in the process hogs a ton a screentime. Should I then just call it a comedic drama queen?
I won't disagree, though, about Nagisa's personality being a "screen-hogging" personality. However, it's not the only Pokémon with that type of personality. Rowlet, Marowak, and Togedemaru (especially the last) all have personalities that could easily hog screen time, but the writers haven't really used their personalities to the fullest. So, there's a chance that, after awhile, Nagisa may not be as much of a screen time hogger when it's not the main focus.
So you agree that Nagisa's personality indeed is quite a screen-hogging one. That's the main point. And no, Rowlet, Marowak and Togedemaru doesn't really overdramatically act that much playful, cute and comedic all the time mor does they go through as much slapstick as Nagisa does. Plus, the LGPE promo factor actually increases that the writers quite likely would use its screenhogging personality. Of course, the spotlight and screenhogging and getting spotlight aspect would presumably be limited to a certain extent since it went to Lana, who isn't that much of an important character, if it went to Ash then it would've quite likely become a serious screenhogger in the rest of SM.