Gosh, this looks so complicated. On meseta pso2 the 1 hand, kudos for maintaining the original game intact so there won't be a riot over changes people do not like. However on the other hand, since they are remaking base PSO2 visuals anyhow, I wish they'd only go 100% and synchronize character models entirely. Giving old players some free fashion items and unlocks will be sufficient to bribe everyone to accept the new system.
Synchronizing 100% personality models does not sound simple. The dilemma is that the old outfits and coating use are modeled to match the old pso2 body. That is unlikely to occur. Well, I mean that I'd be ready to drop a certain proportion of these cosmetics to help keep things intact across versions. Provided that there's a continuous feed of cool new things to replace it, I do not mind. I always rotate out my old looks anyhow. Provided that the character models translate 1:1 it will still feel just like mine.
The instance I can think of is the Monster Hunter Frontier Z collaboration where I can envision the clothing and weapons could unquestionably be given a visual upgrade alongside everything else but that I do not exactly understand how the licensing or the way the lawful side of the cooperation works where I would wish it was as easy as Sega going through and updating the resources but I do not know about how much of Capcom is involved in that procedure.
The same is applicable to collaborations such as the Final Fantasy XIV cooperation with Odin (which exists as far as I know) where I don't know just how much of Square Enix is involved in that for Sega to have the ability to upgrade assets . If it was purely just Phantasy Star-related things (like character outfits, cameos from other games, or alternative Sega-related properties) I could envision that this likely would have been done, or would be carried out. But from the Global variant we don't have the existence of Cougar NX so that I don't exactly know if there are additional complications seeing Sega's properties that might also contribute to not updating everything they could within reason.
I can envision that probably out there we will still see somebody wearing those old collaboration things even if they aren't rigged up to cheap PSO2 Meseta the same standards as fresh cosmetics in a similar way and that there would have been outrage when it was made obsolete or unusable. Collabs who have had their makeup removed nevertheless have their resources exist on the game so those will likely still be accessible for jp players.