Opiates do little to 'mess up the brain's neurochemistry'-- the primary sequela from addiction are conditioned pathways associated with memories, emotions, impulses... during tolerance the opiate receptors become 'down-regulated', but that effect returns to normal after opiates are discontinued and tolerance returns to normal.
I have a paper floating around that addresses the relationship between Suboxone treatment and traditional recovery; if you google 'junig' and 'relationship between suboxone and recovery' you will surely find it.
'Recovery' is not about 'healing the brain'; recovery is about learning to live with a brain that has been permanently changed, so that many different cues induce the obsession to use opiates. The partial agonist and ceiling effects of buprenorphine dramatically reduce those cravings, and in that way block the essence of addiction, which is the obsession to use. Some people consider people on buprenorphine to be 'less clean', but in my opinion it is a focused treatment of addiction-- nothing more, nothing less. There are no cures for addiction; any person who works in the field for some period of time will tell you that there are several chronic treatments: chronic buprenorphine, chronic meetings to induce an 'artificial personality state', or chronic methadone.
Most medications that people take for ANY condition get into the brain and have effects there. People see addiction as 'bad', and so they assume that opiates do 'bad' things. But to the brain there are no 'bad' drugs and 'good' drugs; all foreign substances are going to have a range of effects. Compared to many of them, opiates are fairly benign from a neurochemical perspective. It is the psychological stuff that causes all the problems.
Its neither a full agonist nor full antagonist ....... I believe thats the largest secret -