From the Personal Journal of Rupert Giles Volume 1 by ginar369
Chapter: Entry 2

03/08/2013 04:37 pm

I'm glad that you bring in how resourceful and intelligent Spike is - I always hated the transition to the "dumbed down" treatment that the series used as a means of trying to make him more acceptable to interact with Buffy's inner circle. 

Yeah by season 4 they portrayed him as a bumbling fool. How someone who had a rep for killing slayers became comic relief always baffled me.