The updates GTA 5 requires.

Grand Theft Auto V was released in 2013 by Rockstar Games to mass success and critical acclaim, making it the most profitable and successful entertainment product to date. The series was known for its sandbox nature and the freedom it offered its players; to do whatever they wanted in a stereotypical and over-dramatized United States (Los Angeles). 

The previous titles by Rockstar such as Red Dead Redemption (2010) and GTA IV (2008), featured amazing downloadable content. However, that is not true for their best game, GTA V. The game featured minor story mode updates. With the release of GTA Online, the focus shifted and now the main objective was in turning the game into a trillion-dollar cash cow. Now, that's not wrong, not one bit. If I was in their place I would do the same (I love money, duh), but I would also try to avoid losing the heart & soul of what made GTA a masterpiece in the first place. Here are some of my ideas that can help GTA V be a better game. 

1. Story Mode DLC and updates - One of my ideas was being able to control your online character in offline mode. Obtaining stats for your character offline through training may be a good way to progress in the game. Remote Control vehicle events, Miscellaneous US Military & espionage missions, and more strangers and freaks missions, please.
2. Honor system - The honor system of RDR II needs to be implemented in GTA V story mode allowing the world to react more fluidly to the player's actions in-game. A good honor character should be rewarded with goodies such as secret vehicles, toys, or money. Bad honor results in swearing and cussing by NPCs. A lot of police vehicles drive around waiting for the player to commit a crime. 
3. GTA Online - In order to combat cheaters, Rockstar Games need to develop an in-game system that destroys and annoys cheaters in hilarious ways. One of my ideas was to create a virtual Superman who would pose as an online player and defeat cheaters. 
4. Community - Social Club is a great way for the GTA community to come together. Community events & introducing motorcycle clubs into the mix & would make Social Club better.
5. Product Placement - Yes, product placement may be a headache, but the right ones may work wonders. For example, one of my ideas includes Norton Motorcycles collaborating with Rockstar Games to develop a concept bike! Who wouldn't want to see a Burger King in-game?
6. Details over Graphics - Red Dead Redemption II is a brilliant example of this. The level of detail in that game, from authentic & premium cigarette cards to horse testicles shrinking in winter. From tiny details to the beauty of landscapes while horse riding. The game was a perfect ode to the wild west.
7. Improved physics engine - Although fun and hilarious at times, a craving still lingers for the Metal Gear Solid V sort of technical fluidity. Being able to crawl like Snake would be fun, impractical but fun.