What would you tout as "overspecialized" in this context? To me that statement gives the impression of sacrificing or weakening performance in some important areas to heavily bolster 1 or more others. This is true of some big mons, but I think in the case of some highly controversial mons like Galarian-Darm, Zacian, and Calyrex-S (as well as some past titans like Kyogre or Primal Groudon), the more applicable term is "min-maxed", in that they don't really relinquish a great deal in terms of weakness to emphasize their strong suits (Zacian is made to be offensive, but is not particularly slow, frail, lacking in coverage, or questionably typed as any kind of counterbalance defensively).
I'd argue this almost would be a sign of power creep, with GF going a lot more intentionally on Pokemon with cohesive and synergistic traits than throwing some numbers and flavor-based traits together and seeing what turns out how (I doubt Lando-T was something they saw becoming as huge as it turned out when making it as part of a trio). Maybe it says more about past mon design but I don't think it's a position without a lot of ground for discussion.
I would argue these two aspects overlap in a way. If GF sticks to simple or stagnant mechanics or design approaches, inevitably the only two ways to make Pokemon stronger or more appealing than the old ones are to give them appealing designs, or to give them higher numbers/better use of them in battle. Eventually they run out of workable gimmicks (or at least fail to think of any) and just have to make the Pokemon yet more efficient at stuff they already do.
