It sucks when good users go inactive, but it is a natural part of any online community, and VGC is no exception (long-time users will be able to rattle off lengthy lists of great users from back in the day).
Regarding Ka-pi, I chatted with him the other day (and linked him to his round in the Greatest User tournie to show him that I'm far from the only one who wants to see him return!) - there's a chance he'll come back in a couple of months once his real life is less busy.
Made a bet with LipeJJ and HylianYoshi that the XB1 will reach 30 million before Wii U reaches 15 million. Loser has to get avatar picked by winner for 6 months (or if I lose, either 6 months avatar control for both Lipe and Hylian, or my patrick avatar comes back forever).