Qaurk's Mod might just be my favorite mod besides Optifine. If you don't know what it is, read up on it here. It brands itself as things that could be added to Minecraft. So instead of a rainbow Dorito Godzilla Herobrine dimension, it adds things like birch trapdoors, andesite stairs, dyeable bedsand obsidian pressure plates. However, some things are completely new. Pirates really seem out of place, and there are ghostly mobs that spawn on soul sand. While these mobs are great for a mod, for a small, non-intrusive mod these are not appropriate. Just as a side note, I don't mind any features from Qaurk's Mod, I'm just saying that some might not want these. This is why I believe someone should make a "More Blocks" type mod. This would retain the blocks from Qaurks mod (and add new ones), while not introducing any new mobs, items or tools. This mod would also include vertical slabs. What do you think? Is anyone up to the challenge of this? Let me know down below
P.S. I know that some features can be removed from Qaurk's Mod, but most players will not want to go through to trouble of this.
The late (1.8.9), lamented "The Little Things" had vertical slabs, walls slabs and stairs of most anything, and the ability to combine two different slabs in the same blockspace.
What I'd love to see would be someone solving the general problem(s):
Figure out how to dynamically generate slabs/vertical slabs/stairs/walls from arbitrary blocks. They'd inherit at least the hardness and transparency of their archetype. Bonus points for inheriting other behavior of the parent block, such as redstone power, sand-like falling (might convert a stair to a slab :) ), or even tile entity behavior. Yeah, some of that won't be practical -- half a piston? but the more the better.
Allow these dynamically generated textures to be automatically overridden by resource packs, so people can fix the worst botches. :-)
Having done this, have a config system to select which vanilla and mod blocks receive this treatment, specifying such points as whether they get a wall or a fence, and perhaps manually specifying some of the special behavior.
Taking it to the next level, allow for blocks to be completely config-specified: name and all the block parameters, including classes such as "full block", "wall", "fence", "passable" (e.g., torches or grass), etc. Textures by name or texture pack. Optionally, allow multiple textures or colorable overlays in textures.
Also allow such a named block (including the dynamically generated walls and such) to automatically replace itself with something else, so you can change your Mark I "cinderblock"s into Mark II "cement brick:black".