A sound strategy in itself, but I don't think this really solves the underlying issue: Promoting a post outside of steemit (or the social network the post resides on), can work for that post, but will attract users who, in general, will have interests that match the largest common denominator.
It seems to me that the root cause is related to steemit's form of direct democracy; it's too fine grained. It's like, say, on a country level, every issue in parliament is decided by a popular vote, or referendum. If that would be the case, the majority's opinion would win, every time, eventually to the detriment of minorities.