These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Game Breaker: The unlockable black and white Yoshis. If you thought the game was easy enough with the other Yoshis, the game will present no challenge to you when using the unlockable ones. They can eat anything in the game without taking damage, regardless of the toxicity of the item or foe. They also gain extra health from eating various things, and have eggs with a larger explosive radius than usual.
It's Easy, so It Sucks: The game was designed to bring in younger kids and get them interested in video games, so the game is substantially easier than usual.
Vindicated by History: At the time Nintendo were widely ridiculed for making this a 2½D platformer, with most critics claiming that games like Super Mario 64 and the then-upcoming Banjo-Kazooie were the way of the future. Nowadays 2½D platformers are one of the most popular genres, with few people other than Nintendo themselves producing any 3D platforming games.