Ok, i like some of gkrit ideas. I will just say now what i think of one item i really like: Staff of renewal. It was long time ago since i was think why the f*** it gives +200 health & +175 mana. I was really irritated with that 175 mana. Why couldnt they make it 200 as well. (even with only -20% cooldown it would be nice item imo, but if they give some bonus why isnt it 200/200) So i was very happy when i read:
Staff of Renewal (500 favor)
-- +200 to +300 Health
-- +175 to +300 Mana
-20% to ability cooldowns - Brings into line with BoTS
that someone thinks like i, but then i thought 300/300 is too good. Then gkrit wrote:
Staff of Renewal
+600 mana
+6 mana regen
-20% cooldown
- thats even more stronger! (at the same time i would be really happy to have that good item, but also sad if i dont choose it on one specific build but other guy(enemy) do - he would be too good) So i think it should be little less good than what you proposed (sadly
)
Even before i was thinking: just make him give us +375 mana (no health) and that -20% cd bonus, and it will be fine. But ofc i am for little more if you all are 
so i'm not so sure how exactly to change it, but if according to gkrit, then +400/500 mana & +4 mps(but cloak of night then definitely needs a buff) or +375 mana & +200 hp, or +400/500 mana & +50% mps.
and Diamond pendant definitely must be more different than SoR (but leave -10%cd), and make it equally good (but ofc, assassins would always use Sof rather than DP; it been left for generals who want to have good fave item which reduces cd)
what you proposed gkrit for DP dosnt looks like more diversity to SoR, it's more like even bigger copying of it. I dont know, maybe it is actually good to be, but i never thought that way - to make them even more similar.