I think a good stat we need to have instead of Happiness is Vitality.
Here is my pitch...
Tauri, Guaold*Spelling sucks sorry*, Asgard, and Replicators are all vulnerable to becoming Undead. They would have to put naq into a vitality stat as the game goes on the harder it is to stay "normal".
Those that become undead can be treated at a 200% cost of vaccination. So at the time if they become undead in one week then it costs them x amount for a regular vaccination times 2.
Another interesting idea for this is to take away the Mothership of Undead. If you think about it undead cannot coordinate well enough to run a MS. The undead in turn have a leech effect on accounts. Not only when they attack you do they steal naq but they force some of your units to be undead among them. Similar to raiding but it happens automatically. Perhaps about .5% of the units a person has out joins you.
Also the cost of vaccination can grow exponentially. You can set it to if all the accounts become Undead before the universe time runs out then it is a victory for the undead.
The MS could be outfitted with a special tech that automatically beams up an certain amount of Undead into a time-dilation field at which point they are destroyed and used for scientific purposes. So we can have Science MS's that work to keep the cost of Vaccinations as low as possible so we would have a chance to stave off the Living Dead.
In the end this idea could help minimize the amount of cheap and easy farms. If an account becomes undead attacking it could result in only 25% of their naq being taken or something along those lines to make it unprofitable to attack Living Dead.
If any of these ideas sound remotely fun or interesting please let me know.