Actually, about that post on Musou releases, I'd like to update it with more recent datas (Media Create's top 1000 for CY 2013 helping) and DS and 3DS in the mix, for a better picture
PSP Musou Special / later releases v.s. PSV Musou simultaneous releases v.s. 3DS and DS Musou releases (Famitsu; no "The Best" included; digital included)
[PSP] Warriors Orochi 2 {2008.11.27} - 42,745 / 202,625
[PSP] Warriors Orochi {2008.02.21} - 51,876 / 162,403
[PSP] Dynasty Warriors 7: Special {2011.08.25} - 28,598 / 84,234
[PSP] Dynasty Warriors 6: Special {2009.10.22} - 23,059 / 76,729
[PSP] Warriors Orochi 3: Special {2012.07.19} - 24,518 / 67,570
[PSP] Dynasty Warriors 6: Empires {2010.01.21} - 13,741 / 43,617
[PSV] One Piece: Pirate Warriors 2 {2013.03.20} - 54,509 / 103,757
[PSV] Dynasty Warriors: Gundam Reborn {2013.12.19} - 44,889 / 96,021
[PSV] Samurai Warriors 4 {2014.03.20} - 43,545 / 92,722
[PSV] Warriors Orochi 3: Ultimate {2013.09.26} - 24,825 / 48,225
[PSV] Dynasty Warriors 8 with Xtreme Legends {2013.11.28} - 11,627
[NDS] Dynasty Warriors DS: Fighter's Battle {2007.04.05} - ? / 21,389
[3DS] Samurai Warriors Chronicles {2011.02.26} - 43,044 / 155,059
[3DS] Samurai Warriors Chronicles 2nd {2012.09.13} - 35,806 / 68,360
[3DS] Dynasty Warriors VS {2012.04.26} - 15,607 / 45,870
And here's the updated datas for some of them from MC CY2013's top 1000 (up to end of 2013)
[PSV] One Piece: Pirate Warriors 2 {2013.03.20} - 60,315 / 118,112
[PSV] Warriors Orochi 3: Ultimate {2013.09.26} - 25,483 / 49,492
[PSV] Dynasty Warriors 8 with Xtreme Legends {2013.11.28} - 11,870 / 22,777
[3DS] Samurai Warriors Chronicles 2nd {2012.09.13} - 33,933 / 115,577
[3DS] Dynasty Warriors VS {2012.04.26} - 15,578 / 48,272
The only Warriors effort on DS was something...far different from your usual Musou title, even for a spin-off. On 3DS, thanks to better graphics, Tecmo Koei had the possibility to develop titles more in line with usual Musou titles, and results haven't been bad so far, especially considering how Samurai Warriors Chronicles 2nd was an expanded version of the launch title and it didn't fall that far from the first title.
However, Vita titles are doing pretty well as well and they're ports, so they're cheaper to develop than 3DS-only titles. And, seeing how things are going on Amazon.co.jp so far, SWC3 will probably debut quite better on Vita than on 3DS.