On the one hand, they have to do something about the sh*tstorm of lawsuits which has gained unprecedented momentum in recent years. On the other hand, if they ditch shunning completely they will collapse.
The important thing is they keep shunning apostates. From personal experience, and I'm sure you've known the same, it doesn't really matter if one who is DF'd for smoking or fornication, but otherwise continues to believe in JWs, is shunned or not; they can ditch the shunning there with little cost. They will even advertise it to throw courts off their trail. But if they ditch shunning for apostates.. well. The "matter of conscience" trick will work for non-dogmatic DFings, but for apostates they have to keep a tight ship. That's where the legal battles must target to.