Do my metrics justify changing the MAXDOP settings?
I would investigate the CXPacket issues first - see what's causing those.  Can you identify a selection of queries that cause those wait types?  Can you then see what is causing the problem through the actual execution plan?  You're looking at gather streams steps, and looking for uneven loads coming in.  Try to identify the source of those - a likely suspect is out-of-date / not helpful index statistics.