I wouldn't say they're great or enough to make those forms really any more viable than they already are at upper ranks.
The ferocity edge gave me I believe +3 dam to my water form and +1 dam to my defensive. Likely scales with major minor and nature of those forms though.
The dam reduction was not overly noticeable, but 5% reduction really would not be in most instances where a form has decent dam reduction. (not sure what the % actually is)

Basically, if you have nothing else worth taking though, may as well, if you ever use the other lesser forms (i.e. in def regen vs mass dam redux, you might shift or fight some in it, and every little bit helps)