It's so hard to tell. We decided in January that this dec would be the year. I saved each month and intended to book in oct/nov if prices reduced. In June prices were still about £2800 but when I checked for the holiday I booked, that one particular day was reduced over £700. (i guess thomsons are trying to fill one flight at a time as the week before is over £600 more plus not peak week).
So I checked with my local travel agent (my sil is a manager) for their opinion based on last year.
She said there were deals about (late nov usually) and that most were approx £1700 but she thought they were for 1 or 2 nights and she wasn't sure of the resort.
I was very keen on saariselka for 2 reasons. Firstly it is the further most northern resorts so best for snow and northern lights etc. but also it's traditional and not a large ski resort like some of the Lapland resorts.
I also wanted the holiday club as it has a pool. Esprit are regarded as one of the best and go there too. Another plus about booking with thomsons was that they don't count the sofa bed like esprit do so a family of 4 gets 2 rooms and not 1! We will probably only use 1 but it'll be nice to have the extra space.
If you wait I expect you will get something but if you have set dates/resort in mind then I would book. It is about the same price to go for a week with inghams and book as a ski package (without the ski)! However this is s/c and doesn't include trips so when you add food etc itll cost a lot more for 7 nights.
Have a look on holiday hypermarket as they were offering my holiday for £200 less last week- different hotel but I would have booked had I known!
I'd avoid rovaniemi if you a looking for authentic experience as most on trip advisor say its very commercial, busy etc.
I think if you can get a price for family of 5 for 3 nights for under £2500 then that's a good deal from what I've seen.