It is not clear why this massive attack article was dug up to hurt Dwight Tillery. My only theory is that the John Cranley campaign is trying to discredit Tillery and thus try and hurt anything he may say, like who he would support for Mayor against Cranley. That might have a small affect on the primary or general election, but only if Tillery is seen as an influencer, primarily within the African-American community.
If anything, this gives Tillery yet another reason to want to punch back at Cranley. This article is too complicated to affect the average voter (and is behind a pay-wall), so it's impact is more within political circles (within the city political beltway). It feels more like punishment on Tillery for opposing Cranley. No one gains from this, but a scorched earth fight by Cranley is going to make any political efforts in his future difficult, unless he is trying to court GOP voters, beyond his need for them to win this year.