I've been switching in and out of stances in my last couple of fights, while sometimes i run dangerously low on MP i've found not only it makes my gamestyle more varied, it does indeed at least help in some way to boost the effects of abilities that otherwise are useless under shield's oath effect, mainly fight or flight, being a great ability to hold during 30seconds.

What i'm not sure it does is if sword oath only affect auto attacks or would it affect main WS as well, all in al i think it's a good avenue for varied gameplay, w'ell see what the community has to say =P