I don't know this Microsoft Ensemble thing has got a strangeness associated with it...
I've got a feeling that Ensemble wanted to experiment (as all artist do) and so decided to create AoM to see what would be the reaction firstly of moving into a new style and what their BANG engine would be like in an AoE style game. If AoM is successful (which is highly likely) then I think Ensemble will make an AoE3
My Mangudai will slaughter all those who oppose me.