In large part I think this is also down to how BW onwards the arcs have stuck so much more rigidly to the game story. There simply hasn't been the room for stuff to develop in the way the older chapters did. The RBGY and GSC arcs in particular meandered a lot, with loads of little side-stories and semi-standalone chapters akin to filler episodes in anime - you'd get an issue that was devoted to capturing a particular Pokemon, or the training/evolution of an existing team member. This happens much less in the later arcs. I'm reading XY atm and it's so tightly constrained; nearly every single thing that happens serves the central arc, and there's barely any time to breathe. BW is a bit better for this but it's where this trend started.
Not to mention that in the older chapters captures tended to take more time and effort, but there's an unfortunate tendency in the later arcs for characters to obtain Pokemon very quickly and effortlessly. Y decides she needs a Pokemon capable of Mega Evolving: boom, she finds and captures an Absol. Pearl gets told "fill up your team" by Wake, and quickly captures three Pokemon. The Plusle and Minun Ruby and Sapphire partner with are recurring characters; contrast that to how, in the ORAS chapter, Sapphire has already caught a Kirlia and it evolves into Gallade basically straight away. And then is barely used. This did happen in the older chapters too, but as noted they generally took a lot more time to flesh out at least some team members. Emerald very awkwardly gets three new team members at once, but we'd spent a lot of time with his original three before that (and let's be real his new three were only ever there to be paired with other dex holders' team members and make Gen IV babies).
Lack-Two has a blade-themed team btw (he has Kabutops, Gliscor, and Escavalier in addition to his others, and they all have a Serious nature). But yeah, they're barely fleshed out and are only relevant inasmuch as they contribute to a theme.