Pax numbers at pik will probably be up this year on last year i would expect. Albeit slightly after the icelandic volcano.
Having said that, I will be very disappointed if the route is canned. Have used it as a passenger many times. Its very good to use for connecting to other flights from Stansted. I know that Ryanair doesn't take this into account because it is a "point to point" airline, but the fact is many people fly on to other destinations from Stansted, and some even from other london airports.
It'll be a nightmare for Ryanair crew positioning to/from PIK as well!
The argument made earlier regarding aircraft positioning for maintenance is also valid. However, PIK does serve many of the newly opened bases in bucket and spade destinations so I would imagine the plan is that PIK will maintain aircraft from bases such as AGP, FAO, ALC etc. There will be less need for aircraft to position via STN.
Edited to add: The route being canned is not confirmed just yet though! Lets keep fingers crossed that the exact frequencies for winter have not been decided yet and once they are the route will appear!