From what I've heard ketamine is already (ab)used as a recreational drug since decades back and quite decidedly has addiction risk. Not addiction risk anything like heroin though, and the trips are apparently mostly unpleasant.

Ketamine in its present form is decidedly not ideal for depression treatment, but probably a tradeoff often worth considering compared to the risks of severe and enduring depression. Amine neurotransmittor reuptake inhibitors have quite substantial problems associated with them too (there we arguably really have had a case of the mistaken and excessive wonder-drug status you allude to).

The true excitement of ketamine-based depression treatment is perhaps more in that it is something different. It quickly affects the problematic state, by some mechanism which appears to be quite different from the now "classical" antidepressants. That has potential both as a basis for more refined drugs and more importantly to better understand the real mechanisms underpinning depression.