There will definitely be more contests this year than there were in 2016 (technically two, but only one truly formal contest) and hopefully more than there were in 2015 (two contests). We're approaching ten years of SCP being a thing, so for 2017, there should hopefully be more stuff for all to participate in!
That said, Scantron and psul are both right. They are a pretty big undertaking; there's planning to see if the idea is a good idea, multiple drafts to write up the hub and rules, then finding people on staff to organize, then running the thing itself.
Maybe contests being totally reworked, with an individual contest getting less entries and contests being common, would improve site morale.
I'm not personally a fan of more than four formal contests a year, and four is my upper goal for 2017. I can see the value in multiple contests each year; more ways to encourage different writings on the site, more ways to push people to write outside of their comfort zone, etc.. But the excitement for contests dipped in the past the more you force in, and I'm not fully ready to see if that still holds true.