I started to make a FTB CTM map with the Direwolf20 pack. I made lots of little prototype traps and puzzles which was fun. However when it came to making the overall map theme I couldn't come up with anything good and I gave up.
As well as the things Kaiomann pointed out here are my thoughts:
Portal Gun - Turrets are fun if a bit weak.
Tinker's construct - put parts for nice weapons and tools in some of the chests. Drawbridges could make some hidden doors or puzzle bridges. Clear glass to block pearls and portal guns.
Extra utilities - Magnum torch hidden above the victory monument and entry area to make a safe zone. Rain mufflers for Youtubers. Block update detectors for more traps. Ethereal glass for mob proof doors.
Computercraft - ban turtles.
Q-craft - more hidden doors, walkways and stairs. One-way walkways and doors.
Open blocks - glasses, crayons and pencils add tons of puzzling possibilities. Cannons for entertaining item distribution or traps. Healer and donation station near the VM. Sprinkler for a quick farm.
Thaumcraft 4 - lockable doors. Tainted mobs. Evil bats.
Project Red - timers, sensors, switches and lights oh my.
Thermal expansion - florbs
Mystcraft - Quick transport through portals around the map Turok style. You could put the book to the next part of the map inside the wool chest.
Obsidian pressure plates - hidden/silent pressure plates.