Hmmmm... I understand your point that Bori provided you with quite a bit of interesting open world pvp. Hence your wish to keep it.
But is it really true that you wouldn't have had open world pvp without Bori? Wouldn't there have been more of it in the "normal" adventuring zones, such as Khesh and probably Paikang (due to T4 raids)? Is an extrinsic factor (like the opportunity to gain PvP XP and Prowess faster) really necessary to make people engage in world pvp?
Bori only makes sense if you believe that, otherwise, people would have stopped world pvp altogether, or at least would have done less of it than is the case now. In my view, that is rather unlikely (see e.g. how successful the B&G servers were before people realised that they had to do Khitai over and over again just like on the other servers) - but active PvPers will be better judges of that than I am.
But in any case, a reduction in the grind (OP's suggestions 3, 6, and 9) would probably take care of Bori, irrespective of whether it is removed or stays in the game.