From what I believe has been said in the past (by either Martin or Lee, I forgot which), they do indeed just switch off parts of rides to save money. Parts that aren't broken in the first place. I believe it was stated not too long ago that they have been turning off lightbulbs on the Grand Floridian that aren't even burned out for example.
From the Dec 23 video you posted, there are a few effects working now that were either broken or switched off during my last visit in February (the leap day they were open 24 hours which was my final day on my AP). When I visited, there weren't ANY water effects working at the laughing place scene at all (neither the kind jumping over the track nor the more stationary ones off to the side). There are at least a few working in that video however which were definitely not when I visited.
Either they are fixing or turning on effects due to the extra time allotted by taking Splash off of Extra Magic Hours, or as RSoxNo1 suggested, they're simply switching the effects back on because it's the busiest time of the year and more people would notice things not working (they may turn them back off soon). I'm inclined to think he might be right on the matter, the timing is rather suspect and it makes sense that they'd just temporarily switch back on intentionally disabled effects for the Christmas holiday.
The ride is going down for refurb this month if I recall correctly, so we'll see fairly soon whether the fixes are permanent. Considering that Big Thunder came back from its extensive refurb with major show features still broken though (and some that were fixed are already broken again), I'm not getting my hopes up. Splash has even less time allotted for its refurb and is a far more complicated ride in terms of show scenes (lot more still broken about it as well).