Originally Posted by
Kashii
You could probably answer most of these questions on your own just moving forward with the assumption that trash > bosses in CM's.
I'd go with something like
Talents - some are just a matter of preference, but Shadowfury is helpful for trash stun/interrupt, Burning Rush for gtfo, Grimoire of Service for on demand aoe burst on large trash packs, Mannoroth's Fury also for trash (may be overkill but just sticking with the theme) and Cataclysm if you really need even more damage on trash packs.
Glyphs - Not sure any are CM specific. There is a good discussion of glyphs in the Demo Warlock Guide in this forum.
Demo CM BIS - so basically you're asking about stat choices. There is a Gearing for CM thread which, although the OP tries to focus on Demo many of the replies go back to Destro. Some seem to suggest Mastery > Crit > Multi although if you were gearing for raiding you'd go more like Mastery > Haste > Crit. So clearly Mastery is a must have. Sandman and Copelands are easy to get and decent trinkets. Honestly, by the time you farmed BIS items you could have completed all the CM golds. Of course, if you're going for realm best times then I'd worry about BIS.
And yes, Demo is perfectly viable in Cm's