Tactics for playing as the Dwarves.

not always, because you can take machines – a tent – and go without losses (initial battles, and then the bears with the paw help=).
Moreover, there is an opportunity to build dragons on the second week on veteran difficulty – with them, it's manageable.
Of course, against such heroes as: Hafiz, Tilshek, Kaspar, Deleb, Wingael, Vittorio, Hagesh, it's difficult for them =) (they fall behind in clearing the map and developing).
The main thing is to take machines to minimize losses at the beginning.

The only thing I don't like (and that's why they lose a lot) is the small chance of getting logistics. I don't understand the logic of the developers. What should races with 2% logistics do against logistics heroes? =\ Should they hang themselves or sit near the castle and wait for them to come and knock on the door?

Karl and Ingvar are easy heroes; it's easy to develop with them more or less.