>>34742876I didn't have a problem. While I was out in the field grinding for the 1% Johtomon, I was knocking Pokemon out while doing so, to level my guys up.
The game even throws you a bone at that point - after you beat Morty, you get access to Surf, which lets you catch Red Gyarados and get the Red Scale to trade in for the Exp. Share. Surf gives you access to pretty much all of Johto's map, so you have a ton of opportunity to backtrack/sidetrack (Union Cave, the Route south of Goldenrod, Lighthouse and everything west of Olivine, and everything east of Ecruteak) and grind for experience, try out different Pokemon you've just caught without them being unmanageably underlevelled, and (admittedly) sporadic phone calls to re-battle trainers.
GS' level curve lets you rotate through and try out/evolve a ton of different Pokemon. RBY doesn't really give you a lot of breathing room to try out any Pokemon you've just caught (they're usually going to be too underlevelled to be manageably useful unless you really don't mind grinding) and I imagine GSC's level curve was in immediate response to that.
