As someone who got the pancakes pre-patch 10, Alolan Raichu was barely any help at all. Even with a 31 speed and 160 EV's in speed, it got outsped frequently. On top of that setting up Nasty Plot usually got it one-shotted and damage without setup wasn't great. Maybe I should have utilized screens more, like I did in my Reborn playthrough, but too late for that now.
My point was I agree that A-Raichu would do better as a useful early/mid-game mon, since I can't imagine it being that much more useful as better Psychic and Electric mons are acquirable.