You should steer clear of metaphor topics entirely. They are generally skewed to the aff and prevent the education that comes from clash. Your topics should include an actor (usually the USFG) and a direction. (should they pass legislation or increase/decrease something)
The USFG should end the US of weaponized drones.
The USFG should take action to curtail the Boko Haram.
Germany should leave the Eurozone.
These topics ensure the debate will have a specific topic that neg teams can prepare for and aff teams have the ground to defend.
I'm not going to engage in an in-depth discussion here, but I just wanted to say this: under these strict topic rules, parli just becomes impromptu TP, which appears to seriously detract from the variety, and thus the benefits, of the format.
Just throwing that out there.
This is false for a couple reasons.
1. TP debates 1 topic the entire year. Parli has the unique advantage of providing a wide breadth of knowledge rather than depth.
2. TP is a different format. (they have evidence and backside rebuttals)
3. Parli provides a unique advantage in its extemporaneous nature. That is not a fault of parli but a benefit.
Realistically, adding value and metaphor resolutions just causes Parli rounds to be messy and without clash.