Don't expect people to respond immediately to your posts. Wait a while. People have things to do. It certainly doesn't mean anyone's jealous of you because they're not checking the forums every five minutes.
I know that people at a multiplay like:World off Warcraft, people can spend years, also I know that there was never a singleplay world where you can spend so much time, but ever wondered when there is a singleplay game that can offer even 10 times bigger gameworld and gameplay as a mmorg like WOW?
Daggerfall might have managed it. From Wikipedia: "Bethesda claims that the scale of the game is equal to twice the size of Great Britain: around 487,000 square kilometers. The game world features over 15,000 towns, cities, villages, and dungeons for the player's character to explore." "In Daggerfall, there are 750,000+ non-player characters..."
They're randomly generated, though, which means thousands upon thousands of generic uninteresting locations and NPCs that the player probably won't interact with, visit or care about. Remember quality versus quantity.
At the moment I want to make a: RPG,Adventure,Building,Crafting and online trade in one game and each world can be between 4 hours till 80+ hours large.
I like youre opnion to know if this is a greath idea to make or not.
I understand your enthusiasm, but I think it's important for you to understand that making an RPG is quite a complex task and a mountain of work. It's quite probably the most difficult and time consuming type of game to make. Not to mention games are always more complex than you expect them to be. Start small. Leave yourself a lot of wiggle room for if it takes longer than you think it will, since it will take longer than you think it will.
Don't make your dream game first. Create something smaller and fun for practice. You'll learn a ton which will make your dream game better when you make it.
You claim to have quit your job to work on this game from the introduction thread, but I think you need to realize that game creation is deceptively difficult and time-consuming. The act of actually completing a game is a tremendous amount of work, far, far more than it seems like it will be at first.
So no, I don't think it's a good idea to start with that game. Once you've learned a lot about the process, perhaps, but even then that's a lot for one person to try to make. But for starters, no way. And don't try to compete with blizzard when it comes to content. Simply don't. Blizzard has probably thousands of employees working on WoW and millions of dollars to throw at its development. You're only setting yourself up for disappointment. Don't delude yourself. Even if you are able to create something great, you simply cannot compete with an operation of that scale and magnitude.
As the saying goes, you can have it done quickly, done well, or done cheaply. At best, you get two of the three. If you have no money to throw at the project, then you might only get one.
This post isn't meant to crush your dreams. It simply meant to help you realize that you might be trying to do too much by not realizing it's more than you can manage. Scale it back, make it smaller and if you have time when you're done you can add in some side quests or something.
And please don't disregard what I've said. This advice comes from many, many developers who have tried it already, and they pretty much all say the same things. That said, go make an awesome game - but make it a smaller one!