Yes, in a perfect wimsical world everyone would play Halo and nobody would play Black Ops....
But, here in the real world, Black Ops is the most played game regardless of what console your on, and Minecraft is the second most played game for all the obvious reason (appeal to casual gamers, kids, and pure infinite fun).
Halo is not on top... so what? Who said it would be? Its a great game, its in third, people are playing it... I fail to see the problem.
Previous titles all I played was Big Team, and i still do most of the time, but I've come to appreciate the other game modes, mostly Dominion, and besides... there are no "real problems". just problems you think your having. Other ppl are playing just fine... as demonstrated by the numbers.