Is there anything odd or developmentally problematic with a teenager using a pacifier instead of drugs or alcohol as coping with problem?

Yes & no: Since sensation in the lips sends pleasure messages to the brain i can see where one might develop a pacifier fettish ( keeping it within the privacy of their private space). It is likely more sanitary than nail biting, smoking, boozing etc. Yet other issues arise. I believe many young adults use pacifiers to control the teeth grinding common in ingestion of various rave drugs. Is this a concern?

Yes: Pacifier use is infantile behavior. A teenager who uses a pacifier is not behaving appropriately for his/her age. Gum may be a more acceptable alternative.