Oh god the checkpoints.... fixed! One of the worst things about GTA4 was how awful the save system was. I could never finish that game, or even get more than halfway because of how tedious they made combat and driving during missions. Hated the missions and the side activities sucked ass.
There is a reason Saints Row 2/3/4 got so popular despite starting off as a semi-rip off of GTA:SA. GTA4 went with "lets make this a gritty crime movie, with a scaled back GTA world" ok... they succeeded in making what would have been an interesting 5 episode arc in Sopranos back in early 2000s... however they forget to make a fun game.
GTA5 returns back to gameplay as the focus, even the way missions transition seamlessly into engine powered cut-scenes is vastly improved from any other GTA and most other games period.
It's like they did the opposite of Bioware, instead of pretending to listen to fans, and then do checkbox game design like Mass Effect 3 and Dragon Age 2, Rockstar listened to fans, and then surprised them with innovative storytelling and expanded and refined gameplay.
Rockstar could have easily done a 10 hour story mode, launched with 3rd person cover shooting online gameplay, tied that gameplay to % completion in the story mode, and most casuals would have been happy. Spammed clothing and skins as DLC and called it a day.
Instead they went back to the San Andreas style of open world, and very clearly re-worked all the important and basic aspects of the gameplay. Everything from walking up stairs to hand to hand combat has been carefully updated and refined, the animations, character models, everything... whereas GTA4 felt like it was full of sacrifices and half assed 'modernizations' like the cover system.
I just played GTA4 lost and damned a few weeks back so the controls are fresh in my mind. I was constantly battling the camera and controls in that game, even tho I'm very used to 3rd person games, it's just a clumsy and unsatisfying experience in every way except driving motorcycles.
And the improved more unrealistic/videogamey motorcycle control from L&D is back in this game.
They still have lots of room for improvement with the whole 'interacting with the world" thing.. but that's such a huge challenge that no one has solved it. For example, interacting with people on the street is press the dpad to the right... extremely limited. Fable 1 had better character interaction.
I'm not sure why this one aspect feels dumbed down, but it really stands out in such a detailed world. It's very cool to listen to conversations after missions that feel more real and organic, but it's an about face when you simply try to interact with NPCs on the street. Their only reaction seems to be fear.