I'm much worse. My Musou madness:
Bought Warriors Orochi 1 (JPS2) -> Sold and bought Warriors Orochi 1 (J360) -> Sold and bought Warriors Orochi 1 (JPSP) -> Bought Warriors Orochi 2 (JPS2) -> Sold and bought Warriors Orochi 2 (J360) -> Sold it and Warriors Orochi 1 (JPSP) and bought Warriors Orochi 2 (JPSP) -> Sold it and bought Warriors Orochi 2 (PSP Digital) > Bought Musou Orochi Z (PS3) -> Bought Warriors Orochi 3 (JPS3) -> Bought Warriors Orochi 3 (360) -> Sold Warriors Orochi 3 (360) -> Bought Warriors Orochi 3 Ultimate (JPS3 and JVita)
Don't even want to think about how I bought and sold the other games.
My current collection:
Koei:
-Dynasty Warriors 8 (PS3)
-Shin Sangoku Musou 7 With Moushouden (PS4)
-Shin Sangoku Musou 7 With Moushouden (Vita)
-Sengoku Musou 3 (Wii)
-Sengoku Musou 3Z (PS3)
-Warriors Orochi 2 (PSP Digital)
-Musou Orochi Z (PS3)
-Musou Orochi 2 (PS3)
-Musou Orochi 2 Ultimate (PS3)
-Musou Orochi 2 Ultimate (Vita)
-Hokuto Musou (PS3)
-Shin Hokutou Musou (PS3)
-One Piece Kaizoku Musou (PS3)
-One Piece Kaizoku Musou 2 (PS3)
-One Piece Kaizoku Musou 2 (Vita)
-Shin Gundam Musou (Vita)
Note that in Japan, Musou Orochi 2 is Warriors Orochi 3. The second game was called Musou Orochi Maou Sairin. Musou Orochi Z is a PS3 compilation of the first two MO games, with the visual enhancements from the 360 versions, additional stages, more enemies on screen, and IIRC 1-2 more characters added to the second game.
Would like to get rid of DW8, SM3 Wii, Shin Hokuto Musou, One Piece 1, and Musou Orochi 2. DW8 would be no problem but I have no idea who would take the Japanese games. Suppose I don't really need SM3Z anymore either once SM4 is out.
Capcom:
-Sengoku Basara 2 (PS2)
-Sengoku Basara 2 Heroes (PS2)
-Sengoku Basara Double Pack (Wii)
-Sengoku Basara Battle Heroes (PSP) (Is more like Gundam Vs. Gundam than a musou)
-Sengoku Basara X (PS2) (2D fighting game)
-Sengoku Basara HD Collection (PS3) (SB1, SB2, and SB2 Heroes)
-Sengoku Basara 3 (PS3)
-Sengoku Basara 3 Utage (PS3)
-Sengoku Basara 4 (PS3)
SB2, SB2 Heroes, and SB Double Pack need to go.
Other:
-Senran Kagura Burst (3DS) (2D musou-style game play)
-Senran Kagura Shinovi Versus (Vita) (3D!)