Fundamentally the problem is that ISK:risk is too high in highsec. The ratio can be decreased in two ways: lowering ISK, or increasing risk. One of these is right for EVE: increasing risk. And there is only one right way to increase risk: increasing the possibility and practicability of PVP. Why is PVP necessary? Because it any canned pattern will be learned and optimized against. For example, making "harder" rats does nothing for risk; it just raises the bar of entry. This is why I criticized James 315, who notoriously proposed to "nerf highsec PVE into oblivion". His proposal was basically to reduce ISK while keeping risk constant. Doing this would certainly adjust the ratio but it would reduce highsec to a desert. Highsec is and should be a perfectly viable and fun game area in and of itself.
So how do we increase risk in highsec? Well, see the title. Much highsec ISK generation takes place in deadspace. Thus, one way to increase risk on much of highsec's PVE is to remove Concord protection from deadspace.
Attacking anyone in deadspace would still incur the normal security hit and Criminal flag, and killrights if he was successful. Concording would still occur if the criminal leaves the deadspace pocket; therefore he is stuck there for 15 minutes while the Criminal timer runs. The criminal would be freely attackable by anyone who comes in, including the original victim coming back in his PVP ship.
Lorewise, it makes plenty of sense. Players can't warp in to deadspace. Therefore, neither should Concord. (I remember being afraid of deadspace as a newb for a closely related reason: I did not realize I could warp out. It seemed logical that if you can't warp in you can't warp out either.) It would also help to explain why all those agents want capsuleer help doing missions. After all, if you really had anything like Concord or even the faction police around, why not just send them? My answer is: because they can't get in there.
In terms of game effect, obviously this would supercharge what mission ninjas are already doing. They'd not need to bait anyone, just charge in with guns blazing. The effect on mission runners is more interesting. They'd be strongly encouraged to take many precautions against gank:
- fitting a more PVP style tank
- finding cheap but effective fits to mission in, as versus faction-fit piñatas.
- having PVP friends on call
- sitting a picket alt on the warp gate
- watching dscan like a hawk
- fighting aligned
- finding quiet systems to mission in
- keeping tabs on local and particular players in local
If these seem familiar, it's because these are the same precautions that one takes when running missions in lowsec or null. So, one positive effect here is that in learning to how to mission in highsec, one learns skills that transfer neatly to lowsec and null. Thus we lower the barrier for successful players to migrate outward.