I know there's an ongoing effort to make the core bigger, but I think the problem is not the size that matters, it's what you do with it
Right now you can go to the core to:
-gather crafting materials
-gather sell-able junk
-do ZC
-hunt players
-fight npc
-go to dungeon
-look for weapons and/or ammo
Making the core bigger will not introduce new activities, and so I propose Core Quests.
The core is already populated with different, some times non-hostile NPC, let's use them!
Some of these NPC could ask players to perform a small task inside the core, these actions would resemble typical side-quests from single player cRPG games.
The rewards for these quest mustn't always be caps, item and exp. - they can also be information. For example info on players ("Y'know, I've seen a bunch of 'em V-Tech over at Roboco", "Don't tell anyone, but there's a single Lawyer at the PD", "I've seen that Malakai fella running 'round with a Super Cattle-Prod" ), info on NPC ("Wanna see a Powe' Armor? Go to the Library Park", "There's a mutie with a Turbo Plasma at the Hospital", "Whorehouse?! Deathclaws all over the place!"), and info on item ("Wanna Gatling Laser? I've see one in PV Bio Lab").
Some time ago, for a totally different, unrelated project I've made a random-quest system, and for that system I had to come up with all sorts of quest types, so I took the walkthrough from GameFAQs of a few games (rpg like BG, KotoR, NWN but also some h&s- Diablo, Sacred, Titan Quest, and FPP - Half-Life, System Shock) to make a generalized list of quest-archetypes. This is what I came up with:
1. Fetch.
NPC ask to find a item and bring it back.
Twists:
-the item is protected by hostiles
-the item is broken into pieces
-the item is locked, a key needs to be found first
-owner of the item asks for a favor for the item (quest chain or counter quest)
-the item can only be obtained at a certain timeframe
-the item is generic and can be found at random, bought or crafted
-the item is a trophy obtainable by killing a certain type of enemies
-the item returned by the PC is 'the wrong kind', quest gets repeated
-the item is unimportant, quest-giver wanted the item-owner dead
-the item is unimportant, quest-giver wanted the PC dead/lured to a trap/commit crime
-the item is unimportant, quest-giver wanted to test the PC, start a new quest
2. Kill.
NPC asks to kill another NPC.
Twists:
-target location unknown or not precise
-multiple targets, only one is correct, PC must test targets or kill all
-multiple targets, only one is correct, PC must test targets - killing the wrong one fails the quest
-multiple targets, all must die
-target chain -The first target goes to the place where the second target is, the second target goes to the place where the third target is, and so on. PC must fallow targets to know where all targets are, killing one target too soon breaks the chain.
-target NPC ask to kill quest-giver NPC (counter quest)
-target can only be killed using some special item (start 'Fetch' type quest)
-target can only/must be killed at a certain timeframe
-kill a boss
3. Escort.
NPC asks PC to go with the NPC to some location.
Twists:
-NPC leads the way, PC fallows, normal game-play dangers
-PC leads the way, NPC fallows, normal game-play dangers
-Ambush - PC or NPC gets attacked on the way (scripted)
-Trap -quest-giver NPC turns hostile and summons backup at the end location
-Lost sheep - PC must find a number of lost NPC and bring all of them (alive!) to a location
-Spy - PC must fallow a NPC without detection and/or/maybe protect that npc
4. Talk (hard to make script-random).
NPC ask PC to talk to a different NPC.
Twist:
-Detective - PC must find out the truth, all but one NPC lie.
-Dispute - PC must make the NPC agree on a compromise.
-Deceit - PC must make a NPC believe a lie.
-Decide - PC must make a moral decision between seemingly equal values (e.g. life vs. love, lore vs. law, right vs. good, evil vs. lesser evil).