That's ridiculous. The only one who's guilty of that in Gen 2 is Typhlosion. And I still like Typhlosion. They're not "bigger" versions, they're ADULT versions. Or they follow a pattern, or a theme. Look at Bulbasaur. Base stage, we know nothing. We know it's Bulbasaur.Got it. 1st stage, we see the bulb on its back has sprouted, and there's a flower, but it hasn't bloomed. Legs are a bit longer, too. So, logically, 2nd stage will have a bloomed flower there, and the creature should be larger. And lo and behold, we get Fat-fuck Venusaur, bloomed flower and all. One of my favorite Pokemon to this day.
Does it always need to work like that? No. Obviously Charmeleon grew wings out of nowhere and Blastoise doesn't have poofy ears. But for those people to say, "Yeah, we thought that what the original creator of Pokemon was doing was boring, so we added some RAZZLE DAZZLE SUPRISES in every box!" is so... arrogant! Pokemon wouldn't even be Pokemon if it wasn't for those "boring" evolutions that people bought the games for. Those games are why Pokemon is still here today.
New stuff is fine, but there's nothing wrong with "Bigger and adult-looking" versions of Pokemon. That's what a Pokemon is.