Sacred Soil is Just fine; it does not need an increase %. If your party is taking massive dmg that you cannot keep up you're not managing your succor's preemptively. SCH have Fel-Illumination 20% Healing Potency Increase 20 seconds 120 Sec CD, Rouse for pet increase 20% 60 sec cd i believe. "whispering dawn" Split cast heals between SCH and Eos/Selene. SCH should only be mitigating dmg on raid members, And popping swift-cast aldoqium/Physic or Lustrate if a raid member falls to low. Sacred Soil is fine SCH is more than capable of doing anything if you know how to properly set up before the situation arises. In addition to the content you may be performing your gear is probably not up to par with the content you're trying to do. You want raid heals go to WHM, Medica/Medica II, Cure III, Regen/Shroud of Saint's GG all set.

Pop a Swift-Cast+Succor+Sacred Soil+Micro Manage your fairies position along with binding the embrace key= OPNESS!

Cheers!