If you ever modded, you know that feel when you mess parenthesis. So, I want to suggest various tools for troubleshooting and managming. For example, tool to seek mistakes (at least most obvious) in parenthesis.
1. Make debugging and creating mods easier
2. Should decrease amount of bugs in mods and maybe even in core DDA.
1. Watch out! Wave of noobish mods!
2. Hard to code due JSON (not proofed).
Ways to create it
Plugin for notepad++. Notepad++ is quite common tool for coding JSONs. Difficulty: Variable from Medium to Very Hard
Entire software. Tileset Maker, Missing Tile Checker and Building Editor are good examples. Difficulty: Varies on type. Profession maker wouldn't be so hard while new enemies with special abilities, weapons (?) and very special features like overhaul NPC behaviour and Air-drops can be very tricky.