I did notice this, particularly for Alen. Same pose, always.
For Jymsar though, I actually thought his sprites' lack of change in posture was actually kind of fitting - for somebody who is (at first) tightly wound, you might expect this kind of posture. So, personally, I wouldn't scrap Jymsar's early sprites -- I'd actually love it if when Jymsar opens up more, his new sprites would become more apparent with more relaxed and varying postures, but his older ones remaining for early in the story.
I think one thing to be careful of is not to go overboard. I'm worried about seeing characters doing awkward little dances when they cycle their emotions.