Hero Side: Move the inside detective outside, and or make the detective you get dependant on your origin. Villains: Make the broker Origin specific.
The list of contacts given when you hand in a completed safeguard/mayhem should include either more contacts to chose from or a root contact.
Add root contacts. A root contact once unlocked (mini-arc) allows you to share contacts at that level. Both sharer and sharee need to have completed the mini-arc but then any contact (those unlocked by normal means, not those unlocked by killing stuff or badges) unlocked for that level range can be shared. Level ranges are 1-5, 6-10, 11-15 etc.
Mini-arcs are 2-3 mission arcs that include some of the mobs you're likely to face in that level range.
One Root contact per zone hero side and two villain side. Thus the mini-arcs could also cover some of the story behind the zone.
Where contacts offer a random mission as part of an arc, rather than just offering a single mission they should offer a choice of missions. *Looks at Stephanie Peebles*
Not noticed this villain side but certainly heroside. If two contacts offer the same mission (eg Safeguards) you should be able to auto-complete the mission as though it is being offered by a single contact.
Mini-arcs are 2-3 mission arcs that include some of the mobs you're likely to face in that level range.
One Root contact per zone hero side and two villain side. Thus the mini-arcs could also cover some of the story behind the zone.