Johto was small and the gym leaders regressed in levels. Kanto was crap too. I'd almost rather we got a really awesome, huge region instead of squeezing an empty, easily-completed Kanto in there.
It was fine because it was a Pokemon game but it sure as hell isn't anything amazing. It needed HG/SS to fulfill the huge amounts of unfulfilled potential. Emerald outclasses it until the last two boss fights, which brings GSC as a whole onto a good level. I think I might still prefer Emerald on the whole though.
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