As much as I love Raichu.
No. Not Ash's Pikachu, don't let that Uber ascend to God status,if Pikachu evolves, it would break TV's worldwide, just you wait.
But in all seriousness, no. Pikachu won't ever evolve because Word of God makes it so, because of the underdog factor and the fact that people think Pikachu is cuter than Raichu. I don't truthfully. (Don't worry Raichu, I like you so much better than Pikachu, I think your super cute :D)