This is the million dollar question right now, we’re going in January and I seem to change my mind daily on whether we’ll buy it or not, for the same reasons as you. If we don’t buy it and lines are long I’m going to be frustrated about wasting time, if we do buy it and lines are short I’m going to be equally as frustrated about wasting money. The joys of a modern Disney visit.
I suspect we’ll probably buy it for our AK day at a minimum, $15 is much easier to stomach than $30.
We’ve been to WDW enough times that missing rides doesn’t bother us very much, if we leave not feeling it was worth the price we may not be back though, I hate that we’ve reached this point in our fandom but Disney is consistently making it harder and harder to justify continuing to visit the parks.