Johto's dex is fine. Say what you will about it, but there's no bad design. At worst you can just call some bland. They all fit in very well, and there's a good amount of more "cute" ones that balance against the more monsterous Gen 1 ones, like
>>41655441 says.
I think people complain about it nowadays moreso is because Pokemon designs have grown more over the top and in-your-face with their themes, and a lot of the Johto mons are a lot more grounded and tame, with their themes very subtle.
>>41656421Probably just happenstance. Gen 2 was using a data structure which meant they could only have at most 253 Pokemon. Cuts had to be made sadly, and they probably just thought their designs weren't solid enough or something. A shame since a lot of the Spaceworld mons are better than most designs post gen-3, and better than the equivilants we got in most cases (See; Farfetch'd evo, Lickitung evo, Berserker Pokemon).