This would make sense if you were talking about it in the sense that it was a hugely important thing to have as a separate tool for the player to use. As a simple addition to an item? sounds pointless to even argue this. being able to do more doesn't necessarily make the player happier.
also, the Tanuki suit's simple addition is such a huge change because it has the possibility to completely negate a difficult section of a level. if the effect were lessened at all it would become a useless item in the eye of the player. Saying it's a minor change is a bit hap-hazard.
and the P Wing? I get the feeling they could have made that an extendable item of the raccoon leaf, like with the fire flower to big Mario. This more than likely was decided against it for the same reason as above. It also creates a huge change in gameplay and can negate major obstacles, even more so than the tanuki suit's limited invincibility.
saying that adding a water-centric element to an already existing water-centric player device, that affects a quirk to the specific area's design that is about water no less, is a bad idea? that is just mind-boggling.