I don't think so.
The shitty contract think has been going on for ages, they were forced to change their originally beautiful discography for cool SM experimental music.
The Chinese members bailed on the group for better contracts, working conditions and creative control and Exo just stayed their until they started doing lots of solo stuff.
Baekhyun and Kai joined SuperM for whatever reasons.
All the above and so much more but they never complained at least not publicly so why now?
I think they want more control and respect for their careers. If SM was offering them better contracts, I'm sure the lengthy contracts wouldn't matter.
I think they tried to take the Suju route, have their own label or special mgt team more sensitive to their needs in terms of timely music release, more content etc and SM gave them no chance.
So here we are.