1. Slavers can show up at the vault and kidnapp you dwellers and drag them to the wasteland and you have to send other dwellers after them to save your dweller. The success on saving your dweller depends on their level and S.P.E.C.I.A.L. Slavers can come in a group of 3-7 with guns from a 10mm to a fat man it's all random.
2. Super mutants have 3x the health of raiders and come in a group of 2-5 with weapons from nail board to fat man (by the way the the better the weapon the harder it will be a super mutant will have it) same thing with the slavers but super mutants will drag your dwellers to wasteland and if you don't send some dwellers after them within 10 minutes they will be turned into a super mutant and you will lose them.
3. Bloat flys have 1/4 the health of raiders and come in a group of 25-50 and use their stingers in combat.
4. Giant Radiscopian have 3x the health of raiders and come in a group of 3-5.
5. Ghouls have the same amount of health as raiders and come in a group of 5-10 and use their claws as weapons.
6. When you get better in Fallout Shelter the radio station becomes kinda useless because it calls really crapy dwellers. It should be a 5% for a legendary dweller and a 15% for a rare dweller. Otherwise you can only get legendary dwellers and rare dwellers from lunch boxes.
7. Caravan Traders can come to the vault selling a randomized inventory selling anything such as BB gun, combat shotgun, fat man, sawed off shotgun, slaves (when bought turned into dwellers.) Slaves can be common, rare, and a small chance for a legendary dweller. Caravan traders stay for 1 hours then leave.
8. Security response teams are when dwellers are placed in a new building called security office (holds 6 dwellers) and when an incident happens they track it down.
9. We all know how easy raiders are I say we make them more of a challenge. They should come in a group of 3-7 with stronger weapons.
10. When we kill raiders why can't we pick up their weapons? Where do they go we should be able to pick them up.
11. When a dweller shows up at the vault door there should be random chance for them to come with a weapon or armor or both.
12. The armory would be a upgraded version of the warehouse like how the garden is a upgraded version of diner. The armory will hold double what the warehouse holds each upgrade will double the holding capacity but also double the price in caps.