Unpopular opinion - DRK's 123 Souleater combo, for how often it occurs, actually has the greatest impact from a survival standpoint and amounts to a lot of healing potency per minute. Technically Brutal Shell is more, but you have a lot of cartridge actions to use so there is less of it.

But is the filler in general boring? Oh yes, no doubt on that. Usually what I do is spend 25% of my MP on Dark Arts to enhance my Souleater- oh wait, they removed that.