Of course - IMHO - if they are really going to "take it down for a year or more", why don't they go ahead and spend the money to make it "right". That way they won't have to have another rehab in the very near future to rehab the rehab. Know what I mean?
If you've been out to ride Disneyland's SM - I can tell you - the two years it was down - was VERY VERY VERY well worth it! The ride is amazing now - compared to what it was - it's darker, colder, way freaking smooth track, more stars, the audio music really does enhance the ride, etc etc.
I say - if you take it down for that long of a time period - make it worth it! Don't just "tweak" it - give the overhaul it truly needs and deserves!