I have been thinking, and I think that Surgical Extraction is playable in Dredge. It seems great against the mirror, as well as to remove opponent's hate. What are everyone else's thoughts?
I don't think it is that great in dredge.
1) Leyline of the void is just better against the mirror. Extraction is just a speed bump, but an unanswered leyline is gg. LotV also stops critter deaths from removing your bridges. It also causes a headache for snapcaster decks and anything that utilizes the grave. You also have serum powders, so it shouldn't be hard to open with one.
2) You're not going to be countering opponent's hate, and you need to destroy one in play to get it in the grave for extraction to work. Many time's you'll be bouncing it with chain of vapor anyway, so extraction won't help. Also, you'd only be hitting one form of hate IF you manage to get one in the grave.