Alright, so I made some changes.
Firstly, I changed Surge of Death's bonus to strength to +1 in the first increment, +2 at the second, and plus +4 at the third. I also made it require to be at least 7th level to take it and I made the increments scale up every five levels.
Secondly I believe the Vitality Drain power was worded weirdly. The point of the power was for the Oracle to gain the bonus they took for a bit. I reworded it a bit and I hope it is easier to understand.
Thirdly I added a pair of new revelations, but I still need another one (each Mystery has 10 revelations total, I like to try and be as consistent with official rules as much as possible). Here they are:
Life Link (Su): As a move action, you may touch a friendly or hostile creature to establish a link between your souls. Whenever either one of you is within 30 ft of each other and take hit point damage, you may either take the damage instead, or have the other creature take the damage if you took the initial hit, whichever is you decide at the time of the hit. At 5th level, this includes ability drain or damage. At 10th level this includes negative levels and level drain. At 15th level, any time you or the creature you have performed Life Link with have a spell casted on either one of you, you may choose which one of you gains the benefit of the spell (e.g. if the creature you have life linked with is affected by Cure Light Wounds you may choose to gain the benefits instead, or have the creature gain the benefits instead of you if it was initially casted on you). The effects of Life Link last for a number of rounds equal to your Oracle level plus your Charisma modifier. You may use this ability once a day plus an additional time per day for every five Oracle levels you possess.
Master of the Harvest (Ex): You gain proficiency with scythes. You treat any scythe you wield as if its critical threat range were one higher. At 3rd level you gain Cleave and Weapon Focus (Scythes) as bonus feats. At 6th level you gain Greater Cleave as a bonus feat. At 12th level you treat your reach as if it were 10ft when wielding a scythe, unlike weapons with the reach property, you may still attack targets within adjacent to you.