Totally agree. God help you if a pokemon you used earlier stops being useful late game in Gold and you catch a new one to replace it. You basically can't power level and grinding takes an age. In Gold you basically have to catch 5 pokemon early game and stick with them. HG was slightly better than Gold thanks to ice fang and ice shard, meaning my Feraligatr/gyarados/piloswine could actually beat lance.
And while Pearl league had higher leveled mon, it also had the vs. seeker. Gold's league had the lowest level mon, but having comparable mon of your own to fight them was the real challenge. And Koga's Muk still pisses me off.