I believe that in addition to market research, they need filling the void of franchises such as Star Wars (soon finished), and make new and fresh topics ( and please no more Toy Story or Cars )
additionally, I think is best for the economy of TLG stop paying for those franchises
I think that the new minifig collections is one way to test the market, proof new molds and designs; and likes and dislikes from the people
But from all the designs from the new minifig collections, I think that this greek/spartan/roman soldier is one who has more chance to survive for a mass production
I started this topic, just for see the expectation about new topics, especially the ancient, who is one of my past dream (I want to see Zeus, Poseidon and Hades in lego), but suddenly became in a battle of marketing, and is better, because, if TLG could see this forum, they will see the interest and potencial of this topic