Based on the evidence presented to the public so far...
1. The State doesn't have a cause of death.
2. The State doesn't know where the death occurred.
3. The State doesn't know exactly when the death occurred.
4. The State doesn't have any evidence directly linking KC to the death.
5. The State doesn't have any evidence of prior abuse or history of neglect.
6. The State doesn't have any evidence to suggest KC would be capable (mentally, morally) of coldly murdering her daughter.
7. Several of the State's witnesses (KC's friends) all seemed to turn on her at the same time the media frenzy started, indicating they wanted to distance themselves from her only after the case broke and didn't have issues with her before. This suggests there are other reasons they are all so 'ready' to testify against her, weakening their credibility as character witnesses.
8. KW and DC will both testify that they searched the woods and didn't find a body, which will place some skepticism on claims the body was there since August.
9. Investigators/LE screwed up a few times (eg, additional hairs found in the car, premature/accidental release of jail videos, etc) that may render some forensic and other evidence inadmissible or other technical/procedural issues.
IMO, the State has a lot of work to do... which is as it should be.