Yosuga no Sora: In Solitude, Where We Are Least Alone., Ore no Imouto ga Konnani Kawaii Wake ga Nai. Recommendations
-both series got the same incest, although Yosuga no Sora is a bit more "intense" in the term of it.
-both series have a pseudo-harem on it
Both anime have the brother and sister relationship.
The difference between these two anime is that Yosuga no sora is more on serious drama
and it has an arc in each girl while oreimo 2 is more on hanging out with your sister playing eroge games.
Same type of love story, which is incestual relationship between brother and sister. While in Yosuga no Sora it is described in a serious way, in Oreimo, it's more focused on the comedy side.
The unfolding of the two anime is similar: the protagonist is surrounded by several female characters who all serve as love interests. But the main girl remains his sister, who is jealous of her brother's suitors.
Also, each girl has her own arc. However, the final arc is in both shows focused on the little sister.