I'm running 4e as is (as far as flat math goes, no changes), but even at level 14, goblins are a threat.
You just need to change how they become a threat mechanically. You're obviously not going to make an encounter where the PC's enter a cave and have to fight 6 goblins, at level 14. The scale changes. If there is need of raiding a goblin lair, the PC's can simply dispatch some of their underlings to do so, their time is more valuable.
Higher level fights can take on various shapes. For instance, during a goblin invasion involving thousands of goblins, they swarm the streets of a city the PC's are helping defend. The PC's need to funnel the city's fighting forces into more advantageous positions, but a pair of Hill Giants make that impossible, so the PC's must intervene. However getting to the hill giants isn't easy due to the goblins running interference. So I might set up an encounter with 3 goblin swarms (huge swarm), and 2 hill giants. The swarms essentially represent waves upon waves of goblins attacking. I might give the swarms hefty regeneration, to represent that their numbers get replenished. As such, a level 14 goblin swarm feels like a reasonable threat for its level. It is also a threat they don't have to defeat, if their objective is clear that they have to take down the Hill Giants, though some measure of success could be tied to taking down one of the swarms (like taking out a unit of goblins, might delay their plans, allowing a short rest, or give the PC's a bonus on a future mission).
In an epic scenario, you could use goblins as terrain features. You can have them defending a zone. Entering or moving in that zone costs an extra point of movement, and the entering creature takes some damage, then that square of terrain is safe. Basically this represents a fighter mowing through goblins as he moves, or goblins dying from attacking a wizard's fireshield, or getting impaled by the blackguard's spiked armor, or whatever the DM/PC's come up with. It is also representative of the epic power the PC's have reached, and shows how easy dealing with goblins has become. And yet, they are still a threat.
You could even just talk through entire fights with goblins as skill challenges. For me, 4e encounters are more objective/story telling oriented than simulation oriented, and as such, I find it is the easiest edition to make lower level creatures a threat throughout a campaign. Early on they are the main course, later, they might become appetizer or side dish. You come up with whatever mechanics will be interesting, and will work, keeping in mind that PC's get more and more powerful, and this should be reflected in their ability to defeat well known threats. Then you dress it up with the story.
You just need to change how they become a threat mechanically. You're obviously not going to make an encounter where the PC's enter a cave and have to fight 6 goblins, at level 14. The scale changes. If there is need of raiding a goblin lair, the PC's can simply dispatch some of their underlings to do so, their time is more valuable.
Higher level fights can take on various shapes. For instance, during a goblin invasion involving thousands of goblins, they swarm the streets of a city the PC's are helping defend. The PC's need to funnel the city's fighting forces into more advantageous positions, but a pair of Hill Giants make that impossible, so the PC's must intervene. However getting to the hill giants isn't easy due to the goblins running interference. So I might set up an encounter with 3 goblin swarms (huge swarm), and 2 hill giants. The swarms essentially represent waves upon waves of goblins attacking. I might give the swarms hefty regeneration, to represent that their numbers get replenished. As such, a level 14 goblin swarm feels like a reasonable threat for its level. It is also a threat they don't have to defeat, if their objective is clear that they have to take down the Hill Giants, though some measure of success could be tied to taking down one of the swarms (like taking out a unit of goblins, might delay their plans, allowing a short rest, or give the PC's a bonus on a future mission).
In an epic scenario, you could use goblins as terrain features. You can have them defending a zone. Entering or moving in that zone costs an extra point of movement, and the entering creature takes some damage, then that square of terrain is safe. Basically this represents a fighter mowing through goblins as he moves, or goblins dying from attacking a wizard's fireshield, or getting impaled by the blackguard's spiked armor, or whatever the DM/PC's come up with. It is also representative of the epic power the PC's have reached, and shows how easy dealing with goblins has become. And yet, they are still a threat.
You could even just talk through entire fights with goblins as skill challenges. For me, 4e encounters are more objective/story telling oriented than simulation oriented, and as such, I find it is the easiest edition to make lower level creatures a threat throughout a campaign. Early on they are the main course, later, they might become appetizer or side dish. You come up with whatever mechanics will be interesting, and will work, keeping in mind that PC's get more and more powerful, and this should be reflected in their ability to defeat well known threats. Then you dress it up with the story.
