Having a choice between Phyrexian Rager and Yavimaya Sapherd isn't all that appealing. The option to exile a graveyard is quite powerful, but I would never feel great about maindecking this card. I think this card needed to let you choose two modes in order for it to compete with Black's other 3-drops.
I think this card will be a solid performer for anyone that wants to include it. I like the versatility of being a Rager or a Sapherd variant, and maindeckabble graveyard hate is always welcome since it's super rare. This is also a good card in Recurring Nightmare decks. Cool card.
I think they're pretty different cards. To me, outclassed would imply that one would outshine the other in the exact same decks, which I don't believe is the case since this is better in general midrange decks that don't have a critical mass of instants / sorceries. That being said, I do think Sedgemoor Witch is better at its niche than Bloodmage is at its own.
Like Phyrexian Rager, I think this card is going to suffer from 24th card syndrome a lot. Also, if any card outclasses this, it's Woe Strider, IMO, since Woe Strider basically does everything this wants to do plus more.
I think this card is likely to stick for a while in my list. My black section is having a bit of an identity crisis and generic value cards have been overperforming because they're getting splashed. The only decks that are black based right now are reanimator lists.
Black aggro was never good for us and while Pox style decks were competitive they were no fun at all so my black section is basically just reanimator, a bit of storm support, and value cards. Even at 360 I think this fits in as a very good value card.
(My cube specifics aren't really a discussion for here was more trying to say that if your black section is pushing value creatures I think this will easily make the cut)