Hi Ledge,

Well Caesar has summed it up fantastically.
All these games can be tweaked to fit the personality playing it, one of the great things about the TW series.
If a full campaign doesn't suit you then you can play the short campaigns, where, by the time it all starts to go horribly wrong you should be near completing the set goals.

Those that love the battles put the cities on auto-manage, and those that like the micro-management of an empire auto-resolve the battles.
Personally, I like both so I micro-manage and fight my own battles.

Dip in a toe, and I promise that before you know it you've put the rest of the world on the back-burner whilst you fight just this last fight.....