Well, many people have been adding their ideas to the forum, so I thought I'd add my crazy one
This idea has been plaguing on my mind, and it won't go away until I've actually submitted it to be shot down.
Worker Promotions
Worker promotions require a new unitclass (worker). Workers gain xp whenever they build any improvement except a road. They could also get some xp from wonders and other buildings that give xp to 'all land units'. This encourages more protectiong of your workers, as you are not just giving away a worker if it is taken, but a skilled one. Admittedly, these are biased against the Lurchirp, as they can't get promotions on their mud golems, but they are already better than normal golems.
Skilled I/II/III/IV/V
Each Skilled promotion increases the worker's build rate by 10%
Hardy I/II/III
Each Hardy promotion gives a unit 0/1. That's one defensive strength. This makes sure they go down with a fight. (I've had Lurchirp mud golems defend successfully from goblins before, so 0/2 does make a difference)
Mobility I/II & Sentry I/II
As usual. These allow better co-ordination, and it also allows a worker to see danger and flee from it.

Worker Promotions
Worker promotions require a new unitclass (worker). Workers gain xp whenever they build any improvement except a road. They could also get some xp from wonders and other buildings that give xp to 'all land units'. This encourages more protectiong of your workers, as you are not just giving away a worker if it is taken, but a skilled one. Admittedly, these are biased against the Lurchirp, as they can't get promotions on their mud golems, but they are already better than normal golems.
Skilled I/II/III/IV/V
Each Skilled promotion increases the worker's build rate by 10%
Hardy I/II/III
Each Hardy promotion gives a unit 0/1. That's one defensive strength. This makes sure they go down with a fight. (I've had Lurchirp mud golems defend successfully from goblins before, so 0/2 does make a difference)
Mobility I/II & Sentry I/II
As usual. These allow better co-ordination, and it also allows a worker to see danger and flee from it.