Violence in video games dont deserve a category themselves since Violence in video games have existed even during the Atari/Nintendo 80s age in one form or another.

-The Wii had its traditional/old style with SDTVs (their focus was on innovation to controls , not graphics) while the PS3/Xbox360 went HD (where their focus was graphics but not innovation to controls)
-The Wii focused mostly on Wireless controls while the PS3/Xbox360 focused on pure gaming controls like they were in the past 20 years (until they decided to follow suit to get cheap $$$$).
-The Wii focused mostly on casual games and succeeded from the sales while the PS3/Xbox360 catered mostly well known franchises that established quite well during the PS2/Xbox/GCN era (until they went the casual route themselves and well that failed alot).

In the case between the PSVita/3DS

-The 3DS focuses on dual screen / 3D Screen controls/style
-The Vita focuses on mostly games that do not use special controls/gimmicks whatever you want to call them except for a few such as touch screen , etc.
-The 3DS focuses on more appealing games/less complex to a younger audience while the majority of the Vita's current library focuses on appealing to mid-teen/adult with far more complex styles of gaming.

Violence in video games dont deserve a category themselves since Violence in video games have existed even during the Atari/Nintendo 80s age in one form or another.

-The Wii had its traditional/old style with SDTVs (their focus was on innovation to controls , not graphics) while the PS3/Xbox360 went HD (where their focus was graphics but not innovation to controls)
-The Wii focused mostly on Wireless controls while the PS3/Xbox360 focused on pure gaming controls like they were in the past 20 years (until they decided to follow suit to get cheap $$$$).
-The Wii focused mostly on casual games and succeeded from the sales while the PS3/Xbox360 catered mostly well known franchises that established quite well during the PS2/Xbox/GCN era (until they went the casual route themselves and well that failed alot).

In the case between the PSVita/3DS

-The 3DS focuses on dual screen / 3D Screen controls/style
-The Vita focuses on mostly games that do not use special controls/gimmicks whatever you want to call them except for a few such as touch screen , etc.
-The 3DS focuses on more appealing games/less complex to a younger audience while the majority of the Vita's current library focuses on appealing to mid-teen/adult with far more complex styles of gaming.

But its the truth though, not talking about just genres either, look at Super Smash Bros for an example, does the game include strong/intense violence or blood/gore like other fighters? No it doesnt, Nintendo does it differently and their attention is towards a younger audience who would be easily attracted to their games. Not saying that older age people are being knocked out, but their main priority is on the younger audiences especially considering the fact that as newer generations come into gaming, majority will look at the most appealing thing to them which is something like Mario (and no, I dont believe CoD and pre-teens playing is an example, I think that mostly is a issue on its own with the way parents take care of their children-peer pressure/etc).

As for list of fighters (Due to the fact that both systems are fairly new, the list may be small, bear in mind also that the Vita isnt even a year old yet and the 3DS has a year ahead start (along with other factors such as lack of third party development that affected on both sides in one time or another). Fighters is a bad choice of a genre, I would particulary say rather than comparing the genre exposure on both systems, I would say look at what each system offers mostly, Fighters and RPGs are bad examples of course.

imo, Platformers have a bigger exposure on 3DS while mostly action-oriented/FPS games focus is far more exposed on the Vita

3DS
-BlazBlue: Continuum Shift II
-Dead or Alive Dimensions
-Tekken 3D Prime Edition
-Super Street Fighter IV 3D
-Super Smash Bros. 3DS (Unreleased)

PSVita
-BlazBlue: Continuum Shift Extend
-Mortal Kombat
-Ultimate Marvel VS Capcom 3
-Street Fighter X Tekken (Unreleased)
-Playstation All Stars Battle Royale (Unreleased)