I don't really understand what Wikipedia wants in articles on controversial topics. Describing what DIR diving is and where it came from is pretty straightforward, unless or until you want to get into the schismatic things of UTD and whether the Z-system is DIR or not . . .
If you want to include in an article that the system is espoused by certain individuals with the following credentials/accomplishments (citation) and derided by a second set of individuals with the following credentials/accomplishments (citation) that seems reasonable as a presentation of pro and con arguments to me. It is not that I either accept the validity of the critical opinions or approve of their originators -- but if you want to include opinions pro and con, you include them, with the information to help a reader decide whether those opinions are valid or not.
Otherwise, a purely informational article about what DIR is should be quite straightforward.
If you want to include in an article that the system is espoused by certain individuals with the following credentials/accomplishments (citation) and derided by a second set of individuals with the following credentials/accomplishments (citation) that seems reasonable as a presentation of pro and con arguments to me. It is not that I either accept the validity of the critical opinions or approve of their originators -- but if you want to include opinions pro and con, you include them, with the information to help a reader decide whether those opinions are valid or not.
Otherwise, a purely informational article about what DIR is should be quite straightforward.