I've played any number of games where you conquer territory then raise taxes to build more armies to conquer more territory. For me, SCs and powerful magic are the key selling points for Dom2.

And when I've driven SCs, I've never felt completely comfident in their survival (against other players). There's always risk.

The reason people race for the unique SCs isn't that you lose the game without them (I've won games with national armies and national mages). It's that they're unique.

P.S. How often do VQs actually get played these days?