Would it be better for ash's pkachu to evolve?

yeah if pikachu would evolve then it can't sit on ash's back but it would be kinda cool because it could learn hyperbeam.I think the only thing good would be the hyperbeam part

Thanks for the information.I never knew that raichu could use hyperbeam.

if pikachu would evolve i think that the moves will still be the same but now it can learn thunderpunch

A thunderpunch is a really cool and dangerous attack.It can knock out pokemon in one blow.