Our domain had been under Google manual action penalty until recently. One week ago we finally get the action removed.
However, we made a test creating a new domain and pointing it to the existing website. In one week new domain have 3 times more pages indexed than the domain we removed the action.
So, yes, action is removed and performance is a little improved. But why is it still under some kind of handicap, does anyone have an idea?
Chances are that if you got to the stage of a manual action being taken that some other algorithmic actions where already taken. In addition if a Google algorithm update was pushed out while you where under manual review then your rank afterwards may be different to what it was previously. As has been mentioned in the comments a manual action review can affect a domains trust score and even when the manual action review is removed the trust score won't automatically go back up again it will need to go up over time with valuable content and other positive things that naturally increase the trust score. I would urge you to get rid of the second domain you created as not only will it be detected for duplicate content with your main domain but it may also be deemed an attempt to circumvent Google's reduced trust score on your domain which will affect the new domain as well, and may even reduce the domain trust for your first primary domain.
It will take some time but after 6-12 months you should see things on the rise again, perhaps even less if your site does have very valuable and unique content deemed of value to end users.
