@Kreuzfeld:
altho, I really like your source garg. It is not that much of a believable source, he would not have seen the big picture from his vantage point.
It guess military historians would be the best judges, however I can’t think of anyone who have gone into this subject.
I always find it perculiar that historians cant agree wheither if was a good or bad idea for hitler to send army group center south after smolesk, to get a huge kiev encirclement, and capture alot of unrailed factories, rather than to attack moscow imideatly
because the historians think that the decission was made out of political reasons instead of a strategic view point of hitler.
If he would have gone for Moscow immediately then those four russian Army´s (5th, 21st,26th, and 37th) could have become quite a problem of his center Heeresgruppe. Nevertheless, consider that a problem of fuel supply was comming as well.
But you are right, it was this point we have to consider the most on any IF questions!