Yellow was good but it was hard in the beggining trying to beat Brock.
Though Pikachu was useless against Brock's Pokemon, there were changes to the game which made it easier to beat Brock. For example, Brock's Pokemon had lower levels than in RB, and Pokemon that you could catch before you get to Pewter City were made better. Both Nidorans could learn Double Kick at Level 12, whereas Mankey could learn Low Kick at Level 9, unlike in RB. With these fighting moves, Brock is much easier to handle.