The reason stated when they became unavailable was that
only a limited amount of resources were available for storage/production
of Specialist Games, and Kislev was 'put on hold' to make room for the appearance of
the Araby army.
Keep in mind: this was the same time GW went through
their major restructuring of -all- models considered "archive".
It is a safe guess that Kislev was a relatively slow seller,
but I have never seen any sales figures compared to, say;
Vampire Counts, Skaven, or Bretonny (or for that matter: Araby!)
I actually wouldn't mind seeing a comparison of
the various armies relative Popularity backed up with some hard objective data
(eg percentage of all Warmaster Sales/individual army), but:
Not likely!!
There was a rumour at the time that 'discontinued' armies
would cycle back into production over time:
I don't know if that is the case or not at this point.
I have never heard one way or the other that the Kislev Molds are still 'available'...
One last note on the Discontinuation:
I suspect it drove up kislev sales sharply
during the last month of availability..
I know I purchased a sizeable Army I probably wouldn't have otherwise!!
