1)Campaign Qualities: Flexible Magic Items Miracles (Fickle Universe, Indifferent Universe), Sorcery (Wild Magic, Corrupting Magic), Fear and Loathing, Legendary Monsters
The Dragon Kingdoms exist in the Feudal era, while the Steam Kingdoms have moved to Industrial.
The Alignments will be divided between the Dragon Kings and the New Gods, with every god having a rival on the opposing pantheon.
2)It will be near impossible to get Reason/Industrial gear in the Dragon Kingdoms, and Aetheric (Magic) Items are rarer on in the Steam Kingdoms.
As for race, Drakes and Saurians will get along better in the DKs, while the opposite is true in the SKs
3) I like a mix of seriousness and fun. As an Example, one game I ran was able to be serious when it needed to be, regardless of the presence of a Mary Q. Contrary, Neutral Good Shadowcaster and devoted servant of Pelor.