So me and Fluff were on Skype talking about the layout of missions when I hatched an idea...
Mission Layout EditorAs the name suggests, what this will allow you to do is create your own mission layouts and maybe even test them out in Campaign Mode. Obviously, some limitations will be implemented if this gets added to prevent any exploits such as having a mission where you just collect 10 loot crates without battling anything.
How this will work is by typing out a layout, for example...

Spaces are to allow lowercase letters.
Note: Choosing 'Hard' or 'Insane' difficulty in the editor will change the appearance of some sprites, changing their colours from green to yellow or red etc.
LegendSome of these legends will have an 'x' after them, this is because they have variants. To choose a specific variant, add a lowercase letter to the corresponding sprite that you desire. Do not add anything to a capital letter if there are no variants available to choose from.
/ - Empty Space
↑→↓← - Entrance Point to Map for Player Mech
═║╔╗╚╝ - Boundaries/Indestructible Walls
─│ - Destructible Walls/Gates (Destroyed at Start)
P - Sand Bag Pile (Indestructible, used to funnel the player)
M - Enemy Mech
T - Enemy Tank
J - Enemy Buggy/Jeep
L - Loot Crate
Bx - Buff Crate
Sx - Structure (All Destructible)
Images were provided by Fluffeh/PoTaeToh.Thinking about it further, there is probably a more elegant way to do this. However, let's not run before we can walk.
EDIT
A few points I would like to add• Should this feature be unlocked at the start or at levels 15 or 30?
• After rationalising it in my head, I have come to the conclusion that the items used by the AI in these custom missions should not be chosen by players as they could be exploited by players setting the AI level to 1-5 while being level 30.