When you take a look at raichu, you see a frail mouse with a decent attack. but the way I see it, raichu has some real potential. Qith a set of 4 Deoxys EX and a plasma badge on your raichu this adds 40 damage.
But then what? You've bumped your damage from 100 to 140 - either way you're going to 2HKO most things in the format.
You're better off using the bench space on whatever else is necessary to your deck, and Raichu shouldn't be a primary attacker unless in a tech based deck like Raichu/Flareon/Garbodor.
Still gotta say raichu / nintails is awesome I played it at a league challenge last week and mainly used raichu as a main attacker I found out ninetails was mostly used for bright look and occasionally hexed flame.