I don't think that's accurate. People seem to keep saying this because DOC started to look good individually when put on that line, but the line itself wasn't "improved".
Sid/Rust with DOC - 13 GF - 14 GA
Sid/Rust without DOC - 38 GF - 34 GA
They actually were a minus as a line at 5on5, versus any combination of Sid and Rust without DOC. A lot of the various advanced stats also show this (CF%, FF%, SCF%, SF%). The *only* area it saw a slight improvement was in HDCF%, but even that was marginal (59.4% versus 58.6%).