It *was* indirectly because of the size of the block.  Even at 166 bytes each (or whatever the minimum size of transaction), a 250K block cannot contain 1700+ transactions.  And a number of transactions that exceeds the BDB configuration is believed to be the root of the problem.  I know hindsight is 20/20, but I will give the developers credit and assume testing all extremes from 1 really big transaction to many really tiny transactions probably would have been in a formal release cycle.  No such testing was done, chiefly because this was an off the cuff suggestion, not a formal release.