We have the ability to import structures and change them but this isn't very useful if we can't copy the settings of the structure we're replacing.
My suggestion is that when you type in a Structure ID and it matches a pre-existing structure, all settings should automatically shift to the settings of that structure.
Similar to how the text is automatically filled in when you enter a biome preset ID that already exists.

Ivorforce,

Here are the list of features that are sorely needed:

[Editing]
1.) Ability by command to replace all blocks from a mod with another.
-- Reason: to remove all dependencies from a specific mod
-- Example:
--- /#fill reccomplex:generic_solid modid:*
--- /#fill reccomplex:generic_space modid:*

2.) The ability to replace passable blocks with generic_space, liquid blocks with generic_liquid, and solid blocks with generic_solid
-- Example
--- /#fill_generic modid:block
--- /#fill_generic modid:*

3.) Fix the fill command to replace like blocks, such as stairs in the same orientation as the original
-- Problem: replacing say stone_stairs with netherbrick_stairs looses the orientation

4.) The ability to move, rotate, and transpose the structure before /#confirm placement
-- Example:
--- /#import test_structure1
/#rotate horizontal 90
/#rotate vertical 180
/#transpose
/#move x:5 y:-2 z:4
/#confirm

5.) The ability to replace blocks in a structure in the /#edit or /#export menu
-- Example:
--- (List Blocks) Menu button
--- a new gui comes up with a column list of each block name , and a picture would be great too
--- a button to click on the block id and scroll through all available blocks to replace with

1. exists, see /#fill command, which has a parameter for replacing blocks that fit a specific criterium.
2. /#natural is what you're looking for. It doesn't replace blocks, but adds natural floor and space around the existing structure. I use it all the time.
3. Good idea, but I'm not sure this would be super easy to implement. You can use /#fill to only replace one of these subtypes at a time, then you have to run it 4 times I guess
4. Good idea, but might also be hard to implement. I'll consider it when I next work on the mod.
5. /#map is what you're looking for, it can do pretty much exactly that

Edit: names might not be exact, but search through the wiki and you should find the correct names