Pokemon Anime ending soon!?

Good riddance.

But hey, since Giovanni is finally confronting the World's Worst Trainer, was it ever explained why Giovanni wanted a freakin' Pikachu of all things? Not just a Pikachu, that one specific Pikachu.

He didn't. It was just jesse and james' mission to catch rare and valuable pokemon, and having been thrashed by that pikachu, they consider it rare and valuable for it's strength.