But the difference is the designs still are basically what people thought. Turtwig turns into a bigger turtle and then a bigger turtle with some added minor things. Chimchar goes from monkey to bigger monkey to bigger monkey with some slight color changes each time. All the evolutions looked natural until gen 5 where tepig to pignite and dwwott to samurott happened.
I'll give you Dewott to Samurott, which was unexpected and IIRC did happen due to artists block, but Tepig to Pignite isn't that drastic. I mean not even that much more drastic than Torchic to Combusken, where Torchic suddenly develops humanoid traits when its prevo looks like a snowman with chicken legs shape wise.
And tbh I don't think anyone should be talking about how organic the transitions are this Gen are without even seeing the middle forms first, and thus bringing up past Gen transitions isn't really terribly useful.
But I do feel like that if any of the starters do look a bit unbalanced development wise, it will be Litten. Rowlet to Rowlet3 is already very organic even without a transition stage and would work well enough as a two stage, whereas Popplio suddenly gaining humanoid features can be a reference to the transformation of selkies, as well as establishing the colour change between first and last form by having Popplio's snout and spaces between its 'fingers' be white. I loved that about the Oshawott line: how they had a part of their body covered in the fur colour of its next evolution.