Do you really think that, in a world where the likes of Godric Gryffindor and Merlin are still running around, that someone like Voldemort would have ever been a legitimate threat?
Is this a serious question? Yes, Godric, Merlin, and dozens of other wizards will still be running around. Yes, they will be absolute monsters whose mastery of magic is so great that you might as well call them demi-gods. Nothing; however, prevents Voldemort from being an entity even more powerful and dangerous than all of those old legends.
The bigger note of concern is how it will be muggleborn wizards and witches that will be behind the force causing conflict for the magical world. In canon it is a group of Purebloods that want change and thus want a takeover, I'm going for the opposite. My idea is for purebloods like the Malfoys to be accepting of muggleborns to a certain degree. They may find muggleborns to be a bit distasteful but they have little reason to prosecute/harass them. There are more important issues for them to deal with.
The source of the conflict will be how muggleborns want more power within with the four Houses. The way I have it setup is that there are several different ranks within each of the Houses. Upon being sorted into a House a wizard/witch automatically is given the lowest rank within the House. By doing jobs or further the interests of the House said wizard/witch is able to move up the ranks which gives them more privileges and powers. Given that each House controls considerable territory where it basically has near absolute power those privileges and powers can be considerate. The problem is that muggleborn witches and wizards aren't being promoted to the upper echelons of power in the Houses. It's causing quite a bit of resentment amongst many muggleborns since they are barred from ranks that have the real decision/policy making power. Along comes Voldemort who isn't too keen on this ruling body. He doesn't want to be one of the few wizards with the real power in a House. He wants to rule the entire wizarding world. He realizes that purebloods are content with the current system of power and aren't in a hurry to align themselves with anyone that wants to overthrow that system. Muggleborns on the other hand...they are source of followers for him. I'm not too sure of this switch and how people will receive it.
The only reason I bring this up is because, if Harry is going to be our fish out of water protagonist (which is half the point of being raised as a Muggle), then we need a reason why he was born outside of Magical Immortality Land.
That isn't much of a problem and Harry won't be born outside of "New World". I'm mulling over a few non-Voldemort related methods to get Harry top grow up on Earth.
and this world would shape pre-Harry characters (such as Sirius, James, and Snape) into different individuals, and so on and so forth.
This will certainly be something that I'll have to spend considerable time thinking about. Take Albus as an example...he's certainly going to be a bit different though he I hope that he'll still be recognizable as Dumbledore.
Mostly I just feel like it's an attempt to take the standard Harry Potter universe and set it up on a more "epic" scale, because we now have people like Godric Gryffindor and Merlin running around. And I'm not sure how that actually adds to the story of Harry Potter.
I won't lie...a part of me is certainly keen on this due to the more "epic" scale of the world but that isn't really the driving force behind the idea. What drives me is the love I have for magic systems and how they influence the world. I love how useful the Harry Potter magic system is. From the handy portraits that one can create to the Deluminator to all the transfiguration magic. The problem is that in the books I've always felt that the magic system was subdued by being hidden from the non-magic world. I want a world where magic isn't being hidden from anyone and is being used freely to shape the world to a wizard/witch's will. I want to see how the magical society will develop when it is the uncontested ruler of a territory and isn't hiding from anyone. Also, I've always felt that wizards didn't have much
