Be harsh. The setting is a typical LOTR-style fantasy realm, otherworldly; date irrelevant. This synopsis kind of focuses on the beginning and falls off, because I haven't planned the entire outcome of the story and only have content for the beginning By the way, I know this synopsis is pretty bad, resist the urge to critique the synopsis itself xD. Martin, a 15 year old drunkard farmer's son, struggles daily with his life in his poor village of Urskan. Going to sleep one night in their barn rather than face his father, he drifts off into sleep but to his surprise awakes in a large indoor room with 4 other children his age in the same situation. The door is locked. Confirming with them that they don't know any more than he does, they are considering means of escape when the door opens and an official-looking man accompanied by armed guards tells them they are safe and there is no need to worry, and would they please come with him. They follow. Obviously, Martin and his peers are inquisitive about where they are and what has happened but the porter tells them to hold all questions and conversation. They exit the hallway the room is located in and step outside into the lawn of an enclosed fort in the forest, Martin again stunned to see that it is full of people making preparations for what looks like war. They cross the lawn and enter a conference center of sorts, where the lord of the fort tells them they have been magicked to a parallel world because they are perfect candidates for recruitment into the organization. The organization is Vor-halö, a resistance movement determined to dethrone the corrupt and oppressive Emperor Drethan who controls the entire world. The lord of the fort then goes on to tell them that Vor-halö spans thousands of members(not all of them human!) and operates in secrecy in Drethan's cities, towns and villages. They were chosen because of their character profiles, unsatisfying lives in their old worlds and, little do they know, their untapped magic ability. Basically that's it, more is unnecessary, Martin will be running around doing simple missions at first like subterfuge or persuasion but move up to diplomacy, assassination, things like that. Maybe I'll shift the viewpoint around to another agent, there will OF COURSE be a romantic element and a coming of age story embedded within. Overthrowing an empire is quite a lot though... I suspect this would take two books or a trilogy, if not more. Reminds me of Eragon. Thanks for the read!
We can't judge a story just by looking at a synopsis. You've said it yourself, it reminds you of Eragon, the only thing that'll make it original or set it apart from it is they way your write it. Try actually writing it and posting a few chapters or excerpts, you'll get a better response and reviews. As it, all you'll get are comments of "yeah, it's good" or "no, it's sucks". Not very helpful is it?
A story concept means nothing. I can tell you now, it has been done before. What matters is how you write it, the characterization, the flow, the imagery, all of it. There's no point to asking what other people think of the concept! They'll either say,"Sounds great," or, "it sounds like a ripoff of..." If the idea stirs you, write it. Then ask people what they think of the final story. After they tell you what they don't like about it, revise it, usually several times, until you're happy with it or until you throw up your hands and say the hell with it. Please read this thread about What is Plot Creation and Development?
Like Cogito said, the concept means utterly nothing. All that matters is the writer, who could if s/he was good enough, write a best seller novel despite any concept (good or bad.)