1) That's how it works. Cars don't simply just explode anymore. Though you can kill GTA drivers if you crash with enough speed into their cars.
2) Max out your health if you play in Storymode, in Online you have to rank up to gain more health and build up your strength skill, that also helps to survive crashes. Though usually you do die after a crash. It's just how it is.
3) When the meter is full the Stripper likes you. It's kinda like the dating in GTA SA was. When the meter is full you can take her home for some typical "we can't show anything because americans play this game" blackscreen action. It's a pretty useless feature.
4) There might be mods. But beware that if you plan to play GTA Online you have to remove all mods before going online. Otherwise Rockstar will ban you. Using them just in Single player is fine of course.
5) The Cops are a lot more aggressive. Yes, even on 1 Star they shoot you, on 2 Stars they might even already send some helicopters with snipers after you and it gets only worse from there. (Unless you play online and you sit in a Kuruma, then you can laugh at the cops)
6) There are no 6 Stars, it goes up to 5 maximum. On 5 you will be hunted down like an animal, a ton of police choppers, heavy police car presence and NOOSE (kinda like SWAT) going after you in their heavy cars. No army though like in the old games
7) You have to play further. In the storymode the Los Santos Customs opens when you do the mission with Michael to go after his stolen Yacht. It's about an hour into the game and LSC will be introduced there.
8) Everything can stop working in the game if it's too damaged. Cars break down after too much damage or driving them into too deep water. Choppers and Plane stop working after being shot at too much. It's not a bug.
9 & 10) Nobody knows what GTA 6 will be or where it will take place. Rockstar isn't high on "Remakes", so if anything you probably get a modern day Vice City.
With GTA Online being supported until at least the end of 2018 and Benzies (producer of all GTA's since III) leaving Rockstar for good, there is really a lot of questioning, when and if a new GTA will even be started. I wouldn't expect GTA VI until 2018 or maybe even 2020.
As for the crude mixture of realism and arcade, i think that's just how GTA is and considering the success of GTA VI it works. Though with a new producer at the helm (Imran Sarwar) GTA might experience some changes in the future.