Oh yeah, let's talk about the XY crew right now...
Greninja - Since he was Froakie he's always been a cool Pokemon to watch fight, but to be honest I don't really feel him in terms of personality---nowhere near as memorable as Charizard or Sceptile were to be honest, he's kind of a badass but most of the time is kind of flat. I liked the episode where he and Hawlucha had a rivalry, that one filler with Trevenant, but since then it seems like he never really interacts with the rest of the cast much. Ash Greninja is legitimately hype though.
Talonflame - Eh, your usual Bird Pokemon, not exactly the most expressive but has enough basic character to not feel as dull as, say, Pidove. I still think Swellow and Staraptor beat it out, but I'm glad to see it wasn't sidelined like Pidgeotto, Noctowl, and Unfezant were outside of a few focus episodes they got. The fact it isn't the team's sole flyer I think sort of hurts it though.
Hawlucha - The heart of Ash's XY team as far as I'm concerned, a great battler who can simultaneously be hilariously awkward giving him a nice three-dimensional feel. Plus he gets the most interaction with the other Pokemon it seems and feels like the most developed of Ash's Pokemon, not to mention HE HAS HIS OWN THEME SONG. From the moment I saw Hawlucha I figured he'd be pretty popular and pushed by the show, so this isn't too surprising. P-Pokken tho...
Goodra - Shit. Seriously, it was nothing more than a glorified plot device and the fact it ended up being inserted into Ash and Clemont's Gym Battle, as the final battler no less, pisses me off to no end. Seeing it leave right after only highlights that was really the sole purpose it was meant to fill. I also consider its focus episodes to be some of XY's weakest, especially when Sliggoo evolved into Goodra which felt completely undeserved, and I really don't wanna see it again though there are hints it might pop back up perhaps for the Kalos League. Its final arc was kind of nice, but enough to erase the stench of the gooey devil.
Noivern - I haven't got to when it evolves, but Noibat I have mixed feelings on---it feels like it came in a bit too late, sort of like Gible did in Diamond and Pearl, though on the other hand it replaced the horrible Goodra so I like it more than when Gible replaced Gliscor, the latter actually being a good character and not a cheap plot device. Its interactions with Hawlucha are cute, but it seems to have a weird development where at first it was really weak, then it suddenly seemed to be fairly capable, and then it went and evolved fairly fast. I don't believe we've seen it much post-evolution, since we went straight into Serena's TriPokathalon stuff, so how does it act now?
Braixen - Fennekin was dull, but around the time the writers gave Serena a goal and evolved Braixen I've sort of grown to like it. I used to consider Braixen a gross, pandering design, but perhaps because of the show I've slowly begun to warm up to it---and I'm seemingly not the only one since its inclusion in Pokken suggests it has a fairly big following perhaps. I don't expect Braixen to evolve because its middle-form seems to be the star of the line, something that arguably hasn't happened except with Grovyle, and I hope it never does because I still dislike how Delphox looks.
Pancham - Fucking adorable with those glasses. Every time Pancham's on screen I can't help but smile, and its rivalry with Chespin is really amusing and has yet to wear thin for me---this is the first time I think the show has really carried a rivalry like this without just dropping it. In the past we had small rivalries with Grovyle and Corpish and Buizel and Croagunk, but both of those quickly subsided and never really went anywhere, here it's something the writers seem to push pretty well and use it in fairly amusing ways.
Sylveon - I'm tired of Eevee and its ilk. The only positive aspect for me is its interaction with Bunnelby, which I don't know if that's a thing now that it's evolved since I just watched that episode, otherwise I wonder how they'll keep it interesting now that the PokeAthalons are over and there's not much to it now that I assume it's also no longer shy which was its personality trait.
Chespin - The new Piplup/Oshawott, just like everyone figured based on his design, yet a bit held back compared to those two---but I find him pretty adorable and his gluttony and rivalry with Pancham are pretty good gags. "Rima Rima!" I also like how we have a Starter representing each evolutionary stage right now---makes me wonder how cool a Greninja/Braixen/Chespin character in Smash 4 would've been.
Bunnelby - The heart of the team as far as I'm concerned, turning the "Regional Rodent" into the team's big-brother figure was the greatest idea in the history of the series. The eternal straight-man to the antics of all of its friends, not to mention a rather skilled and useful battler, it was so fitting that one of the Pokemon TV channels is entitled "I Love Bunnelby"---because truer words have never been spoken. Bunnelby is the best Pokemon in the HISTORY of the entire series.
Luxray - Really nothing much to it beyond serving as Clemont's main battler, but I do love seeing a random old Pokemon get pushed into the spotlight without having to promote a new game or remake. I wish this happened more to be honest, like imagine if Ash's Grass-type happened to be an old one like Tropius the writers decided to show some love to for no reason? Though I guess that could've tied into ORAS...kind of sad that didn't happen now.
Dedenne - My favorite Pikachu clone honestly, and a cute character who doesn't overstay its welcome. The writers use it sparingly enough that it doesn't get on your nerves, and being sort of an "attachment" to Bonnie forms a great dynamic.
Squishy - Who'd have thought a (anime-only?) Forme for a Legendary could be such an entertaining character? One of the more unique Pokemon to have ever traveled with the cast, its design looks kind of lame yet something about it is oddly cute, and the "wololol" goes a long way as well---plus the fact this cute little dude is basically like a higher intelligence is a fun twist.
Inkay - Adorable. After the failures that were the Best Wishes Team Rocket Pokemon, despite being neat Pokemon in themselves, I was glad to see the writers remember the Team Rocket Pokemon could be both villains and cute characters in their own right. Inkay is kind of like Chimecho and Mime Jr., though he actually gets to fight, and I like that nice mix even though it's kind of odd seeing him hold his own against all these evolved Pokemon especially after Gourgeist evolved. The gag with him dressing up as Pikachu is inspired, and I want that to be a real thing in Sun and Moon.
Gourgeist - Glad to see it getting more attention now, it bugged me how it seemed to get less screentime than Inkay originally when it was a Pumpkaboo such as not getting to appear in the Diancie Movie or its short though Inkay did. I remember thinking female Pyroar was the best fit for Jessie in Kalos due to the hair style, but really Gourgeist is the true Pokemon who was made to be teamed up with her.