People who are saying things about cards needing to be in "every deck" have no creative building skill and are why even more casual groups are turning more into "totally not" cEDH cause all the run is value. (Yes that's probably a bit harsh, but at least online I see way too many samey deck lists which I partially blame on EDHrec). Tantrum/Rant done.

Yes, some cards offer a lot of value, but that doesn't mean they need to be run. It depends on what you wanna do with the deck. For example, I'm a HUGE Phyrexia fan and when [[Yawgmoth, Thran Physcian]] I knew I was gonna build Tribal Phyrexia theme. Outside of happenstance cards, I keep my non-phyrexia related cards to a minimum. No aristocrat cards, Nest of Scarabs, or the like.

http://tappedout.net/mtg-decks/father-of-hell

Other mono black CMDRs that can easily have unique builds are [[Horobi]], [[Liliana, Heretical Healer]], [[Toshiro Umezawa]], [[Gonti]], and [[Korlash]] to list a few. Some commanders do wanna learn into similar builds such as [[Syr Grim]], [[Bontu]], or [[Yahenni]], but even then you don't need to be locked into the same build as others. You might hear arguements about "well you'd be dumb not run card X cause it's so good" but even then, that means nothing. Prove them wrong and break the mold.