I would be strongly against it. The world of Heroes is like the world of Middle-earth, and introducing aliens, in my opinion, would ruin the game and alienate a lot of fans who are already hesitant to switch from the 3rd installment. I think what we have is enough; I just wish there were more diverse campaigns and larger maps where you could encounter the main enemy after a few months, rather than after just 6 turns with powerful armies.

You don't understand. These won't be aliens in the literal sense; they will be more like "fantasy" aliens. For example, their ships fly not with the help of some kind of gravitational or rocket engines, but with the help of special magic. Do you see what I'm getting at? And their racial bonus could be that, for example, a hero moves around the map not on the ground but in the air and can reach areas that other heroes cannot reach for a certain period of time. I'm sure this won't turn off fans; it will only add even more interest.