First inkling that you�ve won/lost an MP Game?

[Shovah32]

Unlike Xietor, I believe domes are a useful part of almost any strategy. Even with poor scales, a couple of domes can protect major production/research centers - you'd be annoyed if your enemy drove your capitols unrest up by several hundred points if you needed capitol only mages.

Domes can also be useful for moving large armies around in relative safety. If you're opponent is fans of mass army(or commander) murdering spells then setting up a path of dome-covered provinces can allow your troops to get up front mostly unharmed.
Combine them with flying/teleporting(not into your domes) squads of SC killers - obviously to take out SCs who try to destroy your armies - and you can maintain armies well into the late game, although of course it gets harder in enemy territory.