A clear case of you can not please all of the people all of the time.
However a few observations. 
I agree with Rob in that K&C has the largest variety of WWII vehicles and figures from
different theatres of operations. Their current WWII inventory is probably more than all other brands combined (ie. Figarti, FL, CS,
TG, Britains). 
K&C also has the largest range of WWI items (even not including The Lighthorse series).
They also cover the mainstream subjects such as Medieval, Napoleonics, American Revolution and ACW.
They offer the following series not covered by other brands :      
Ancient Greeks
Life of Jesus
The Alamo
The Real West
Streets of HK
Imperial China
US Navy
Luftwaffe
RAF
Kreigsmarine
Napoleon in Egypt
plus have produced a good variety of diorama items to complement their figures.
K&C have in the past done Russians and Japanese and have indicated more Russians are in the pipeline.
Regarding Pacific Australians there was a poll about Australian figures in 2009 and Pacific Australians came behind WWII North Africa and Lighthorse. Since then we have had 30 figures in the Lighthorse series with more to come. This month we have a good release of Australians in North Africa.
Regarding new Artillery I think a clue has very recently appeared on the K&C home page.
Regards
Brett