Why is it the same platitudes about the TU-154M are rolled out again and again after any significant event?
Of course its hard to discount other causes, but assuming that the a/c was in a good maintainable state (and it was a low time airframe with probably VIP maintenance throughout its lifetime) I'd rather more lean towards what we already know.
The evidence reported (albeit early stage) leans towards the inevitable highly likely conclusion. Why can't anybody call a spade a spade nowadays?