General DiscussionEsports does not include WCA 2015 qualifiers

yeah. i wondered that too.

Lot of tournaments are not included. I played dozens of Starladder games and none of them appeared in esports tab.
I guess it depends on the nature of the tournament, like it won't take ones played in private lobbies (like starladders matches are).

Is it hidden by PerfectWorld servers?

but DAC which is hosted by Perfect WOrld does show up in dotabuff.