Ok all. I was thinking… This is a crazy concept… triangles… I know its probably crazy but still.
There would be a few benefits.
By the way I made this image.
Also one of my favorite games of all time roller coaster tycoon uses this method.
Biggest potential problems IMHO: How to tell whether it should slope or not, how to tell it to slope from within qubicle. The second one is a much bigger issue than the first, I can’t see a way around it unfortunately and limiting it to terrain seems kind of wrong. Also it detracts a bit from the cube-y feel.
first, awesome mockup… 
second, and please excuse my ignorance, but would every triangle be similar to those you’ve represented here? meaning, they all have a “peak” which merges into a flat (block) plane? in other words, there would not be a triangle whose peak was at an angle itself…
Love the mockup, Gnomoria has something similar in the form of ‘ramps’ which are, or can be, at the edge of a block so you can walk up and down it.
Perhaps if you simply had a terrain option to implement a ‘ramp’, that could solve the movement issues you talked about, that is if there are even siege weapons/ vehicles, but as @Xavion mentioned it would take away from that cubey vibe, and perhaps just add a whole world of issues in itself?
Well I dont think it would take to much away from the cubie feel as long as the ramps were positioned strategically and used sparingly. Roller coaster tycoon was a great looking game and it had slopes like this.
I dont see why you couldn’t have a triangle merge into another triangel…though I dont think that world look supper nice.
Ill do another larger mock up at some point to show how a world would look with slopes like these.
Oh and i can almost guarantee that the level generator does not work from within QC. If the worlds are randomly generated as they are in minecraft as I think they will be then a triangle is no big deal.
What’s the program you used for this,
definitly not qubicle.
By the way: amazing rendering.
Sketchup + podium
(:
Love the mockup!
And I agree that this would be good (at least most of the times that I think about it 
).
From what we’ve seen so far the only way for the little dudes to get to another level of the landscape has been by using stairs, and that would just be weird if your out exploring the wilderness. It could be done using smaller cubes that make natural stairs, but I don’t thing you want too much of these high resolution areas, so things like soft, rolling hills would either have too high steps to look soft or be to high res so that they just look messy.
If you define the art style as blocky then yes, slopes could mess that up. However, if you define the art style as retro then it would be ok, since many old isometric 2d games use them. The landscape doesn’t have to follow the exact same rules as the rest of the models.
Three “slope tiles” would be enough, to keep the simple style. A straight slope (one side up), an inner corner slope (2 sides up) and an outer corner slope (one corner up).
Oh and I second the “almost guarantee” that the world generator has nothing to do with Qubicle.