Although Industrial craft has many things to offer, it doesnt take too long to experience most of it. So I came up with the idea of something that is getting better the more of it you have: War-Robots/ -Machines!
They could have different tiers reaching from easy-to-build wooden ones to mega-expensive quantum droids. They should have a bit weaponry with them, so you can combine melee and shooting infantry or something (maybe even support for weapon mods like balcons and sdk's...), as well as a bit of AI that allows them to get easy tasks to guard/ wander around/ stay in groups/ mayybe even attack another player and his robots by inserting the full in game name of him... As I have no idea how hard it would be to code these things, and how well they would fit in the mod, this might be just an idea for a major addon...
The second idea would be crossbreeding between mobs.
They could be trapped in some glass tanks and you extract genoms of them (just like seed packages) that you can analyze and breed. They could have various stats - like the plants - like easyer to slaughter, more droppage, faster egg production...
You get the initial DNA sequence by hitting a mob with a DNA sampler of some sorts, which you then put in the tanks, so that the mobs grow. By putting three connected tanks next to each other, you have the chance to get a better/ completely new DNA (again just like the plants...)
As an input you would need of course food for them (a possible use of the canning machine), antibiotics, and something like a water filter (a small, cheap device that you can easily produce).
If you don't insert food, they starve/ dont grow as fast, if you don't insert antibiotics, they get diseases/ maybe the DNA could get bad as well and if you don't insert new filters, there is a chance for the tank to burst (however) and the mob to escape.
As I have no idea how people like these ideas, I didn't took the effort to think about crafting recipies, but that shouldn't be a problem for me...
da_sechzga