I guess the question is whether your goal is to make all three stats equally useful, or to make sure the attribute damage mechanic is used equally on all three stats.
If it's the former then increasing the utility of the other two stats with initiative, magic, dodging, etc. would be a good way to go.
If it's the latter then making sure enemies have a wide variety of attacks works. Psychic/psionics, poison, ensnaring, soul damage, etc. would all help.