I'm a filthy casual who hasn't played since Blue, and picked up Moon to check out the hype and what all's new. Pretty close to finishing my dex (first time, since there were no online trades for Blue and wasn't that hard into it back then anyway) – down to just Scizor, Porygon-2/Porygon Z, Slowking and Solgaleo that I need other people to get (finally managed to use some WT Popplios to get Electivire, Magmortar and Milotic).
Before Pokebank, with the smaller available pool of monsters for people to ask for, I had a shot at trading for what people wanted – it'd take some work, but I was close to having what I needed for their trades.
Now, I might be able to still get Solgaleo for the spare Lunala, but everyone on the other monsters' listings seems to now be asking for Arceus, Mewtwo, other-gen starters... there might be a few still-doable trades posted occasionally, but they'll get snatched up so much faster now that anyone can request anything.
Before, people would settle for a Popplio (though I think the two I have left are "breedjects", the other one had better moves), but now there's not much reason for someone to when there are so many more monsters available.
Thank god there's still r/pokemontrades (once I figure out how that works), but dammit I was so close, ha.

(Already had a rant a week or so ago about how the GTS doesn't recognize that trades holding the proper items will evolve after trade to what people have requested, too – that alone would let me get the last few I need and remain antisocial, ha).