These changes would obviously just apply on PVP servers.
Outside of molten front and tol barad world pvp is essentially just small time ganking. Even raids on stormwind/org are relatively rare due to the tuning of guards and the ability of players to just stay unflagged until the invaders are at a more killable level.
Make anyone in a faction based town killable.
Put the guards down to the level of standard 85 mobs.
Reward players for both offense and defense (perhaps by inflating the requirements for and rewards for the city killer/defender based achievements.)
This would encourage players to use the other Horde/Alli cities more if they wished to avoid conflict.
Neutral cities and Neutral Quest hubs would maintain sanctuary status/murderous guards against PvP.
I would absolutely love to sign in and see the Org AH packed full of 85 alliance, surrounded by corpses.
Would other people enjoy this?