In terms of playable races I've always wanted to try an open-style where as many "bipedal" races can take place; not just humans, elves, dwarves. We would simply work out a balanced way for each race to function. If someone didn't want a "default" race they could simply explain their character and race, all the benefits and downsides and we could try to find a way to introduce that character in.

"The year is 266 AE."

"At the start of the cycle, two-hundred and sixty-six years ago a war raged across the land, destroying many lands, dividing others, and killing so many.
The humans of Nastron ripped each other to shreds over the land, dwarves siding with the western kingdom Astronus; the elves choosing the eastern kingdom Nastronia.
This war led to catastrophic consequences.
Weapons of unimaginable strength in technology and magics were used and resulted in permanent alterations to the very land, climate, inhabitant and world as a whole.
After the end, the humans vowed peace; as well did the other elder races. Now, the same threat arises as Nastronia races begin fighting over land once more.

As long as the inhabitants of the First Plane have quarreled over land and mere properties, seemingly locking them in a limbo of war with each other.
Nastron being the largest continent, it is seen as the prize of all prizes for the competing nations. New Nastronian humans battle tirelessly over what they believe to
be their land. While the elves and dwarves aid once more, now with fae-folk and valley-folk fighting.

While the nearby island-continent of Shi and larger nearby continent of Triope prepare for war to unfold, the distant land of Esortia watches on cautiously."

"However, that's not why you're here."

"You're here for the wish aren't you? The limitless wish, no strings attached, you know? I take it you got my poster?"

"All-powerful artifacts don't come around very often, you know? Not every goblin would be willing to part with such a sweet sweet prize, you know?
A limitless wish; an endless stream of wealth, a peaceful conflict to this inevitable world war, is it fame?

Whatever your wish is, is not my concern. I'm just the master of this little game. If you don't wanna play I can't force you, you know?
If you wanna play though, just step right up. Don't be shy.

I took this die here, and made my two wishes. First, a giant, unbreakable tower filled to the brim with horrible monster and challenges that all work for me.
Secondly, cameras for the whole world to see the marvelous events within of course.

A goblin's gotta make money, you know?

All adventurers welcome, I don't discriminate on the number of legs or the color of flesh, you know?
I'm ready when you are, first adventurer(s) to reach floor one-hundred get a wish granted of their own design."

_

A structure which size rivals the gods stands alone in a mountain-range, stretching far into the sky, kisses the heavens in the very center of Nastron, a war-torn land.
It seemingly appeared overnight on a particularly gory night of battle between the opposing nations of New Nastronians and Astronians.

Thought far from any settlements, it was easily seen for miles, a black pillar stretching to the very heavens. Many of each race joined together to greet this addition to the landscape to
be introduced to the "chance of a lifetime" a small goblin sitting a stop a giant twenty-sided die spoke clearly to them. "The tower you see is real and very amazing, you know?" He started.

"The one that can make it to the top of this bad boy gets a wish, a seemingly limitless wish from what I've seen. This tower is unbreakable, try to prove me wrong. No promises on your safety though, you know?
I packed this baby with thousands of monsters that all work without question for me."

"I decided I have a pretty good thing going here and have very generously decided to give away my last wish to anyone who can complete my challenge, you know?"

Upon the first few entering the endless black tower through giant, contrasting golden doors around the world televisions flickered to the live-feed inside the tower. It wasn't long before those
who had entered died, but the trap was set. The blood-thirsty nation wanted more of the tower, and hopeful adventurers set out to meet the tower's challenge.