I would have to use external libraries other than default python (and I abhor not understanding the methods I invoke) and spend many more hours modelling, texturing, and designing a 3D world, a huge task for a single developer.
If it is your dream game, i wouldnt worry about such tasks. If you want 3d go 3d.
You see, I wanted to create something based on world interactivity instead of awe-inspiring graphics or gory combat systems. I wanted it to be lightweight, so that users wouldn't have to worry about performance issues or the like. So far, I've built it from the ground up as a top-down 2D game. But I'm concerned over how it would be received, since the gaming community can be anal about having high-resolution, 3D models in every game they play. Not to mention, the Last of Us has recently reminded me of the extra immersion such graphics can offer.
There is nothing wrong with 2d graphics. Not every one cares about high end resolution and 3d. Now-a-days everyone is so hip on resolution, that they plan so much on 3d/resolution and the time it takes to work on it, that they forget to work on game content. Game content is more important than what it looks like.
. I have pawned off 90% of new games within the past few years because of this. Take the COD series for example. Their single player has swindled down to something like 5-8 hours to beat. The multiplayer is pretty much the same as it was the last 4 games. A little here a little there added, but nothing significant. At this point i got so sick of call of duty, they couldnt even pay me to play it. I havent bought one since black ops 1, and pawned it within the first 3 days after being bored of it. A lot of games are like this now-a-days. So worried about what it looks like, or in COD's case, bringing up the next one for christmas regardless of it's content.
It doesn't matter what your game looks like (Of course the better 2d look you have the better). As long as it is fun to play and has some originality. If the choice was a crappy, but really good looking 3d game and a crappy looking, but really good 2d game, I would pay 2 times the money to play the 2d game. In fact i do that now.