Swordsmanship & Unarmed Fighting
In GTA San Andreas you could basically use many different fighting techniques in melee combat, from Karate to Judo. There was a "Hack & Slash" mod for GTA IV.
So why the HELL is there only one add-on sword (which is a Katana) and no real unarmed fighting style mods in GTA 5!? I know we have the Spiderman beta mod (which is currently getting a well-deserved upgrade) and the better combat mod but who doesn't want to see an epic martial arts battle in Rockstar's semi-futuristic gangster game?
. Diffrent Swordmanship & Martial Arts Styles ( because switching from Kendo with a katana to raw Tae-kwon-do in a fight is just so cool.)
.Dual Wielding ( We all know how cool that makes a certain Black Swordsman in SAO. Plus it's cool.)
Training ( Different arenas around Los Santos provide opportunities to prove your rep and become a badass fighter, plus there are economic benefits too.The more you fight the more points [which level up your skills] are gained.
Combat Improvement (Even the opponents spawned by the Superhero mods use the new combat system, expect to be sent flying by even a regular NPC if you don't train hard. No more lame fist fights which cause the opponent to run away if weapons come into play, use your head and win the fights like a boss to earn stamina and health.)
Special Techniques ( Think Bleach's Hakuda, Zanjutsu and Kido, Ruroni Kenshin's special techniques and Street Fighter's techniques. There are special fighters scattered though the city who posses these powers, don't get cocky if you're using a superhero mod.