Old best LC = no XPB, no SPB, no "SP cheat" low level monsters, no all kind of "pay to win" boosters, much harder monsters ( yes we killed orc sergeants in a full parties in Prokion

), no exp. lock, upgrade to +15 only and HS very rare drop, no tons of pointless P2 pets, no annoying invisible barriers, no recall cards so the only way to "powerlevel" was to fight strong monsters in a equal party.
Of coarse devs never managed to balance the classes in this game so sorcerers (cousing lag and no party skills, no stun) and TKs (very low damage) had a hard time to level. At least healers have been welcomed in every party.
Monsters A/D, and exp. gained can be adjusted for a concrete server so I hope we will get a true "old school" server.