Ok ok ok, we've seen and talked about this subject NUMEROUS times. I was watching some video on a site called "Screw Attack" I'm pretty sure most of you might know that site from their now famous (and still highly debated) Goku vs. Superman Deathbattle. Anyway they had one where Pikachu fought Blanka from Street Fighter and they did some interesting insight on Pikachu.
They mentioned that it is highly likely that Pikachu has reached its maximum potential, which I agree with despite plot clearly putting his power in flux. I mean defeating all those Spearow in episode one meant that the EV training from that massive victory raised explains why Pikachu's speed is off the charts.
Taking that into consideration along with other factors. Raichu would be an incredible Pokemon for Ash to have! Put back Volt Tackle instead of Electro Ball and we have lift off.
Some of the cons (and major reasons why we'll never see this happen):
Merchandise! Come on we all know that is the primary reason for the little yellow rat still being in its 1st form
Ash won't be able to have it ride around on its shoulders anymore
Writers will have to come up with even more ridiculous ways of making Raichu weak at the beginning of each series, seriously new Pokemon that are clearly weaker beating up Raichu isn't going to be easy to pull off in a reasonable manner
Team Rocket...if they can't contend with Pikachu (who at times pulls off what seems God-like power) would not have a chance in Hell with Raichu
What do you all think?