I was happy with the first 150. Red and Blue already had Gengar, the evil ruler of awesomeness, so I would have been ok without too many new ones. He even still looks cool.
Of course they would have to do SOME new ones. Now they're just running out of ideas for decent new ones. Look at combee.
A short script of the guys who make the pokemon featuring John and Jeff.
John: Hey jeff, the boss wants us to do some more pokemon.
Jeff: OK John but i'm out of ideas, you?
John: I know! We'll do a... slice of toast pokemon!
Jeff: With a bite taken out of it!
John: And we can put a big bowl on its head and make run round as a buffet for all the other pokemon!
Jeff: Genius! Are you writing this down?
Pretty accurate script I'd imagine. Now that i've got that out of my system i'll carry on.
G/S. Not too many bad new pokemon, could have done with a few less.
R/S. Too many again. Some stupid ones, but introduced some pretty cool ones too.
D/P. This is when they overworked Jeff and John. Far too many new ones, i had only just learned the names of the 3rd gen. And most of them were pretty stupid.
There's lots more but i've wasted enough of your time and space with this post, so... I'll Go.