I.e. Buster Sword overthink, seems like there's a large amount of 'This is a different game! It doesn't need to follow the rules established by [ ]....but it'd better follow this one! It has to!', whether that means the BS getting thrown by the wayside, remaining unremovable (and having that role further underlined by it being the strongest), and/or maintaining Ultima Weapon as the strongest sword. As far as I can tell, in the OG, the acquiring of every weapon other than the starter weapon was 'non-plot related'--meaning, like so many other things, the arsenal of weapons acquired was a virtue of the battle system, rather than something occurring in the narrative. Similarly, though, the depictions of the characters with their 'base weapons' was also out of necessity, only in this case, one of graphical capability, rather than storyline importance. For the "Ultimate Weapons", the purely battle-system based thinking is even more apparent...they are comparatively difficult-to-obtain, unlockable weapons that compensate you for this with power, with everything about their design screaming 'super badass ultra pwr damage 2thmx!' rather than anything remotely serious (or relevant). One of them might as well have been the head of a dragon you mount on your fist that shoots flames out (and that would've been badass!). But it seems to me that all sides are taking the ol' stabby-stabby punchy-punchy a littleeee too serious.
More than anything, though, this IS a new game. So whether first weapons will be more important, or final ones maintained, out of all the areas you can expect OG dogma to be maintained or disregarded, this is one where it feels safe to say all bets are off.