First of all, instead of being able to choose between 3 wonderful starter Poke'mon (which evolve through 3 separate stages - giving the game a strong feeling of a story arc) and your arch nemesis selecting a Poke'mon of the opposing type, powered with your Poke'mon's elemental weakness who evolves at the same rate your starter Poke'mon does, you get stuck w/ this asshole...
Who only evolves once, and who you would find EXTREMELY EARLY ON in both Red or Blue version anyhow. So having him as a starter is completely useless.
Secondly, he's gotta waddle behind you around on the screen the whole fucking time, completely eliminating the 'lone warrior' atmosphere of the game.
If you were a kid who grew up during the Poke'mon craze, you really put a lot of emotional investment to your party, and when you'd battle up against someone at the playground, you really felt like those were your POKE'MON. This vibe is totally ruined with the reminder of 'Hey this is supposed to be Ash from the cartoon who's Pikachu follows him around... not actually you.'
And if that's not bad enough he has to annoyingly bitch the whole adventure! What a pansy.
WEREN'T YOU ALSO RESTRICTED FROM REMOVING HIM FROM YOUR PARTY!?!? Sack of crap game, I tell ya.