It would be bad if a buff from PVP will also make on side stronger in PVE and so i dont think the buff will leave Cyro, also i dont think the buff will be really strong, maybe a bit more health and damage against fortress..
They've stated that PvE will benefit from the Elder Scrolls because they want everyone in that faction to feel like they are part of the bigger picture. They will probably just give out buffs according to the total number of scrolls being kept by your faction across all the campaigns. And to alleviate the super buffed faction if you have all the scrolls (hypothetically), each individual scroll will probably provide very little to the overall buff of the total number of scrolls being kept by your faction.
EDIT: But that's just my reasoning on the subject and is in no way confirmed
