I'd like to see some more bosses added into the game to make the Scythe actually viable to add into the game like I already talked with you about Gretar.
Aside from that I think adding the Mythical Cape into the Vote Shop would be more ideal seeing as we have the Inferno and the Ardougne Cloak in there and those are the two of the better capes in game.
The Sanguinesti staff could be added to Skotizo's drop table as it is pretty poor for how long it takes a new player to kill or even secure the kill. Maybe keep the drop rate the same as prayer scrolls as there isn't much use for the staff other than maybe for avoiding burning any scales or trident of the seas charges at Kraken boss. This one is a little harder to determine because the really isn't a lot of uses for it.
For the Dragon Hunter Lance I love your idea of finally putting in a boss with a slayer requirement like I have suggested to Gretar before. I think also adding in: Cerberus, Dagannoth king, Giant mole, Vorkath, Tekton, (some i'm probably not thinking of) with high level slayer requirements so we could have some good drops from these including large pure PKP drops from harder bosses. I don't believe we need a whole lot of items from these higher level slayer monsters however making 1-5k PKP drops available would create incentive for people to get higher slayer and at the same time adding more pkers into the mix.
Everything else you have in your topic looks pretty good, IMO some items such as all the PvP equipment should have been added in when the PvP armor was redone.