One
extremely minor thing that might be worth noting about the Unova Elite Four is that they had an actual
reason to have only four Pokémon. ... uh, in BW, at least.
I think the intention there was to balance out the fact of having (effectively) two Champions: 4*4 + 6*2 (28 - or 29 counting the mascot) is actually more than 5*4 + 6 (26). Having teams of five would've meant a disproportionately long Pokémon League and noticeably more time spent on battling - I can't blame them for making that choice, to be honest!
It wouldn't necessarily have been a matter of
difficulty - I mean, you can go to the Pokémon Center in between the Elite Four and N, and N himself heals you before Ghetsis - but the actual length of the event was already longer than usual, and they probably just didn't want players to lose steam before they got to the important part. It was a pretty effective solution to a pretty reasonable problem, I think.
One thing I do think was a problem here is the abundance of single-typed Pokémon - between Caitlin and Marshall, seven of their eight Pokémon had no secondary type, which also means every single one of Marshall's Pokémon being the same type "combination." I think even a four-Pokémon boss can do better than that - the fewer Pokémon there are, the less of an excuse there is for them to be so redundant to each other, you know? But on the other hand, Shauntal is a four-Pokémon boss done perfectly well - even without a fifth Pokémon, she actually manages to be one of the tougher Elite Four in the series in my opinion and actually stands out as the strongest in the Unova League pretty much every time I play!
In any case, the sense of ending fatigue I got from how long Sword and Shield dragged on during the Championship arc has definitely given me a new appreciation for how well BW's mid-League story sequence was paced. The
two separate tournaments against five-Pokémon bosses - with the only really notable plot point that happened during either of them happening being Bede's challenge - just felt like padding to separate the also-awkwardly-paced story segments around them; this was an example of sticking to a traditional gauntlet ending purely for the sake of sticking to a traditional gauntlet ending, and the fact that BW went out of their way to mitigate that feeling is something I respect.
B2W2 are somewhat more questionable, because there is no reason to have only four Pokémon for the majority of players; the result in this case is that
Challenge Mode ends up "on par" relative to the rest of the series, which... not only does that not affect a majority of players (leaving everyone else with four-Pokémon teams for no reason), but it's actually a valid criticism of Challenge Mode in itself (I'm positive I've seen
someone say so here earlier -
Yung Dramps, was it in one of your posts?), and I can't help but agree after playing it.
Remembering how much harder B2W2 seemed than most games when I played them as a kid
I was the kind of player who skipped content regularly and ended up underleveled for everything, though, I went into Challenge Mode
plus various restrictions - no Poké Marts, no in-battle items, set mode, and I feel like there was something else I'm forgetting expecting to struggle on a comparable level as an adult, but it was pretty underwhelming, even below average, in terms of difficulty even then.
It was still a super fun run, though - it gave me a newfound appreciation for how mindbogglingly content-stuffed B2W2 are and how many side dungeons and fun features there are, and I ended up with one of my favorite teams in the series. It was just way easier than I expected. XP
Buuut yeah, I didn't lose a
single time past
Cheren ... who actually did beat me up many, many times because I did not have a good team at that point - and I don't think I even came
close to losing at any point except the final Colress fight.
Many of the bosses in Challenge Mode
do have some particularly well-planned strategies on paper (like, Clay has an incredibly cool sandstorm team), but none of that actually worked out in practice because they just never had the time to pull them off successfully.
This is another reason why giving bosses EVs in Generation VII was an unexpectedly fantastic decision that should really be standard going forward!
By X and Y, though, there was just no excuse - or even an obvious
intention like B2W2 (nothing like "it was misguided but I can see why they thought it was a good idea") - and I get the impression that they just remembered doing it in BW, didn't think about why it worked or why it was necessary, and blindly took the same path. I appreciate that we changed back immediately afterwards when they realized how silly that was, haha.
So, uh, yeah! The story issue with BW's Elite Four is very jarring and I definitely agree that they should've done more
more reasons why Alola has the best Elite Four by far, but I actually think the four-Pokémon teams
were an acceptable choice for BW - just one that got progressively
less acceptable as the justifications for it got weaker and weaker in subsequent games until Game Freak (rightly) returned to the normal five-Pokémon teams.