Instead of to kill a Guard of each nation I think it should be like the Spy mission :

go to a sector in border zone to find and kill a special bot(transport from opposed nation)
you have 30 minute to do the job.

rewards must be good.

Game need more existing mission combat than the advanced combat mission (chaining tycorps) and CtC (racing)

And you could get like 300-500 combat xp for it.