Yes, the absence of any impact crater and no recognisable parts of the fuselage, apart from the vertical stabiliser, increases the likelihood of significant airframe disintegration prior to hitting the ground. What we have not seen is the debris field along the flightpath, which would provide much more suggestive evidence. The video of the plane in flight definitely shows it to be on fire, with some limited trailing disintegration (although being dark it's impossible to see the extent) and a steep downward trajectory followed by the large explosion on hitting the ground.
There's nothing in any of this to rule in or rule out a possible cause, so statements about the cause from Iran or Ukraine at this stage can have no validity (any more than guesswork on this forum). It has been reported that there was no emergency call from the flightdeck, so that adds nothing either.
The airframe was only three years old, although recent maintenance just 2 days ago is bound to arouse suspicion. Until there is more evidence, anything is speculation. The BBC is reporting that Ukrainian officials are now rowing back on early assertions of a "technical problem" with an engine and are now saying investigators need to ascertain the cause.