I am a relatively new DM, I've run probably a dozen or so sessions over a couple of years and I really want to start a homebrew game. I had an interesting idea and I'm sure I'm not the first to have it but I want to know what you all think.

My idea was to have players essentially placed on a brand new world by a god and charged with building a mighty empire in that god's name. I imagine it starting out as a very much survival and exploration game through completely uncharted, unfamiliar territory. Eventually the players find a suitable location and begin to set up a village and the god gives them more people to live in and run the village. Perhaps other gods have also placed seeds on the new world and now the players have to deal with diplomacy or warfare between empires all while slowly building out a glorious empire in a new realm. Essentially Civ. Could it be fun? How could I make it fun?

My major concerns would be, how do I keep the party adventuring and doing fun and interesting things, not feeling obliged to settle into life as rulers of the empire? How do I deal with backstories? The best characters always have complex and rich backstories but of course these players basically poof into existence? What about loot and rewards? Do you all have any thoughts or opinions?

It's an interesting concept, and It certainly could be made to work - but it's quite a departure from the standard game, and thus it would be a lot of work, especially for a new DM. And since it's so different, it might be less accessible to Players who are expecting some variant of the Standard Setting - complete with Elves, Dwarves, etc.

Standard High Fantasy typically takes place in a historically and social complex world - lots of Races, legends, ruins, & ancient artifacts, old forgotten gods, etc. D&D is repeatedly stated to be about Combat, Social Interaction, and Exploration. Without people, or a developed world, the last two are hard to do.

If I were to attempt something like this, I might make it the re-colonization of a long dead world, or continent. What was this place like? Who lived there? What were they like? Why is it dead? Could this happen again? Uncovering the answers to those questions could be part of the central Campaign adventure ( especially if someone is fighting to destroy this world again, or preserve it from the "invaders" ). This would allow you to have the empire building idea that seems to be central to your idea, and still provide Players with a complex legendary world, a mystery, and regions to explore. The could map out the ruins of the world around them, explore, and find clues in the ruined world around them to try and determine "what happened here". I might also not make the world completely dead, but simply devoid of intelligent life - keeping flora, fauna, animals, creatures, and monsters in the world.

If you have the Players' colonization effort multi-racial, with Elves, Dwarves, etc. along, you could still have complex cultural interactions from the beginning, amongst the colony. Characters could still have complex backstories, but their history could be party from the place they left. If the world around the new colony turns out to only be mostly dead ( i.e. there are small pockets of survivors after all ), you could introduce new cultures and races for them to interact with. Or, maybe this place is fully devoid of intelligent races, but there are other colonization efforts from other places ( Planes of existence, continents, crystal spheres ), and/or sponsored by "other Gods" ( as you suggested ) - and introduce new cultures, and new conflicts, that way. So we have lots of exploration possibilities, preserve complex Character backstories, have social/cultural interaction possibilities, and lots of Combat possibilities ( with creatures and/or other colonies, or factions within their colony ).

I think the basic concept could be pulled off. You would need a lot of Player buy-in for your original idea, and it would be a lot of work - but if you can pull back in some of the standard components of the game into your world, in a way that still fits thematically with your original concept, I think it could be a lot less of a stretch, while still preseving the "building a new empire in a ( now ) empty world, struggling against others trying to do the same thing" concept that you started with.

I'm just brainstorming :) If any of it is useful, or sparks your own ideas, run with it :)

Best of luck, and have fun with it! :)

Rich Backstory =/= good character is one thing I'll mention. As long as your characters have motivation for what they are doing, they can be good characters that develop session by session.

Ive done a bit of wilderness survival in a campaign I'm currently doing. I would advise in your case having other individuals or groups wandering about, and have random tables for different possible random encounters in the wild- this is the perfect time to pull out beast and plant monsters IMO. 

As for building a kingdom itself, I would look into Strongholds and Followers, it's a very similar concept of creating a fort and building renown, and I both think it would be very applicable and have heard some very good things about it from several people

Honestly, that sounds fun what I would recommend is by having the party starting at late tier 2 early tier 3 and have the party going up against rival groups of adventurers sent by other gods and split the party towards the end with them ended up as being gods for their races. Also, this seems like an amazing idea to have multiple campaigns in the same world