It bothers me aesthetically that the Missiles don't have "bomb hitboxes". Like Marth can Fair a power missile, clearly be inside an explosion, but not even just take damage or whatever. [/microjohn]
Anywho, Transform on Sheilda bothers me tremendously after seeing Samus/PT lose this mechanic to focus more or less on removing jank (Samus) and building up each character as their own unit (PT). Sheilda just sorta still has the ability to transform despite other examples of the mechanic being purged, with the defense essentially being "oh, its not broken yet" or "legacy", to which I reply that the ZSS transform was not broken, and what about the "legacy" of the PT mons who were around for like 5 years before they were all available in PM? Those were all changed for design reasons, not necessarily balance ones, but it seems Transform is resistant to this train of thought.
Is it because Sheik and Zelda would need new down B's? Seeing as Zelda has already seen radical change, and a melee semi-favorite Ganon has received huge change as well, I don't see how giving Sheik a new tool that was like, I don't know... a Olimar Nspec hop to cover the "loss of recovery" or Zelda a means of manually destroying Din's in a grander fashion to mirror Transform's current use for her would hurt too bad for fans of each character. If anything, it would let Zelda have some breathing room to be worked on as swapping to the superior sheik wouldn't be a factor anymore.
TL;DR : It just seems incredibly inconsistent with the rest of the roster who had similar mechanics. Ice/Fire mode and Offense Up don't even compare to swapping to a whole other character.