First, I would have a hard time taking Dean Holcomb's word for it. If you had scientific evidence that the shoe print matched shoes retrieved from Damien, that would be a different story. Now, the second problem you have in your hypothetical is that a shoe print at Baldwin's house is not much different than a husband on trial for his wife's murder and his fingerprints are found in his own house. Well, there is a perfectly good explanation or reason for those fingerprints to be in the house, or shoe prints at Baldwin's house in this case, that don't have anything to do with involvement in the murder. Now if you changed it to an expert was able to match a shoe print at the murder scene with shoes retrieved from Echols, then it would be a different story and would certainly sway that pendulum toward guilt.
Regarding the remainder, you are being a bit presumptous on what I would think. If a knife was found in Damien's house and an expert could say that within a reasonable degree of medical or forensic certainty, that that knife is the one that caused the injuries, not maybe did or possibly could, but within a reasonable degree of medical or forensic certainty did cause those injuries, then obviously that would also sway that pendulum towards guilt. But again, that is straying away from the evidence as it is. The problem with the evidence as it is is that it is way too remote and way too large of a leap to say there is no reasonable doubt.