Power Creep
Like many multi massive online role play games, WildStar too started off as a game with gear grind. Don't worry gear grind is still in it. The problem with these games is that there's something called power creep. Power creep is when the player gains strength throughout their journey in the game without the gain being balanced. This means that you get more strength, abilities, powers, damage and you're overpowered in the earlier content you're through with already.
So, what's the problem here? Well, since you're done with the old content, nothing interesting drops there anymore and it provides no challenge.
Content Is Live - Content Is Love
Thus, to keep the player entertained new content needs to be added constantly. A good example of this is World of Warcraft. There have been so many add-ons already and for a good reason. The way the game is designed if there's no more content the game will die. At some point, you have reached the end of the chain of content. You get the best gear and highest item level and the only content that is still relevant to you is the last content that has been added.
Fighting Power Creep
So if you want older content to stay interesting we need to implement some way to keep the earlier content challenging.
Horizontal Progression
Guild Wars 2 did this by having no gear progression (also known as vertical progression). With vertical progression, the player needs to play content to gain power which is required to progress through the content. Horizontal progression, however, challenges the player's pure skill. Every additional content adds new mechanics or combines old mechanics requiring the player to always improve themselves throughout the content. The good thing about horizontal progression is that you reach the best gear quite early in the game and yet all content stays equally challenging.
Scaling Difficulty
Another way would be to provide different difficulties. In Diablo III the content won't ever get too easy. Well, at least the greater rifts. You can keep increasing the difficulty to compensate for the damage increase you gain.
Downscaling
Downscaling is the progress to lower the player's stats to the point they're equal to another player that plays on this level. The biggest problem with downscaling is getting it right. Most often decreasing stats isn't everything. Unlocking abilities, skills, passive effects and much more make it hard for simple downscaling to work. However, if you're getting it right, this is a good way to go.
Loss of Interest
Thanks to our procedure(s) the content is now always equally challenging regardless of your gear. Yet, having done all the content and gotten everything from it, why bother running it? Just for the fun enjoying it? That might go well a few times but in the long run, that won't work.
When I was brainstorming and discussing this with other fellow WildStar guildmates it has shown to be the hardest step to reach the goal of replayable content. Of course, people do something just for the fun, but if you want to keep them engaged you need to implement a goal for them.
The problem with most goals is that they're either short term or long term but not for infinity. Well, at least attempts of long term goals resulted in grinding.
Skins and Unique Items
If you have several players who like skins, implementing these as dungeon rewards is a good way for people to keep running it. Same with achievements. Both of these only apply to a certain handful of players who are interested in said content. There's a problem with this though. Even if you tell an achievement hunter to run a dungeon 100 times or add 50 item skins to a dungeon, at some point the player will be done with these leaving them without a goal.
Backtracking
Another option would be to say, every time you find an item in a later content you have to rerun the older one to imbue or improve this item. This will most likely increase the number of people running the older content assuming they didn't quit the game yet. This will probably tick players off having to redo over and over again. The other problem here is that there will be players running it when it came out and stop until the next content update comes.
Renewing Special Effects
During the brainstorming, I had this idea of implementing special effects like auras and armor or weapons looking different but running out of energy over time requiring you to run the content again to keep the effects up. Apparently some game developer I don't know the name of (sorry D:) already had this idea. I don't see much wrong with this except it only applies to a portion of the player base that is interested in their looks.Unique Materials
I'm doing a game design course right now and I read through a game design document of someone else that was about making a game with its focus on mining and fishing. This brought me another idea. If the instances have unique materials that are required not for gear but consumables, chances are high that people will keep on running the content to craft those. Also, a good option would be soul-bound or account bound crafting using those materials. Keep in mind traders might not be able to run those dungeons for those materials then.
Instance Bonuses
Just like Guild Wars 2 giving away gold for running 8 different dungeons (paths), giving a bonus to gold gained from a certain raid wing or WildStar providing bonus essences to certain dungeons having these bonuses switch through. If the bonus is worth the time, it will most certainly attract all kinds of people. Sometimes certain currencies are not as interesting to the player however there might always be one primary currency that the player will need for all their goals. Whether it's better skins, equipment, achievements or building something.
Conclusion
I hope this brainstorm and discussing, I did, helped some people develop their own opinion and ideas. Whether or not it is possible to add replay-ability to content from MMORPGs is a question I cannot answer as of yet. Aside from all this, it's your choice to leave power creep in or to compensate for it. Yet, it would be cool to see an alternative game. I know I called Guild Wars 2 out for having a horizontal progression but technically it doesn't. I guess I could make that another topic for another time.
