In the past, most of my martial arts campaigns were run sporadically, a short stint into oriental adventures, or my own home brew with bits and pieces from d20, bits of GURPS and other games like Hong Kong Action Theater. I rarely found any one game system had exactly what I wanted, so I'd freely cobble stuff together as needed. This shorter length felt natural, to me the same way running a horror adventure from time to time felt natural. I liked doing mini-campaigns about once or twice a year because I was into martial arts and I liked watching different kinds of martial arts movies. I assumed for most players, an excursion into Kung Fu or wuxia was okay once in a while, but most wanted to return to bog-standard fantasy eventually. So I would tend to run my martial arts campaign settings for a few months at a time. That changed around five years ago or so when I decided to try to make martial arts more a part of my regular campaigns. I've been running wuxia campaigns and fantasy campaigns with heavy wuxia elements now for a while and they've become my default. Particularly with my Wandering Heroes of Ogre Gate groups over the last two years or so, I've learned a lot about keeping these kinds of campaigns alive.
This is just a list of things I've observed. Some of them are specific to the Wandering Heroes of Ogre Gate system or games that employ similar approaches to Kung Fu techniques, others are more general.
Wuxia is a Perfect Fit for RPGs
It's easy to go into a wuxia game thinking it needs to be this impossible thing to run that perfectly emulates the genre. In reality it is a lot like other genres that get transported to the RPG medium, and it's a perfect fit in that respect. We called our game Wandering Heroes of Ogre Gate for a reason, because wandering heroes are a staple of the genre. You can't get much more D&D than characters wandering through the wilderness, from city to town, etc. Add to that elements like secret Kung Fu Manuals, corrupt officials, larger than life villains, feuding sects and you almost don't need to prepare; adventures just unfold after you drop the PCs into the setting. Plus if you bring in the supernatural sub-genres (Hopping Vampires, Fox Demons, Immortals, etc), you open the door to more stuff that's a perfect fit for an RPG. My advice is don't hold back on the supernatural elements unless you are aiming for more pure wuxia or kung fu game.
Players Can Learn to Enjoy Wuxia and Kung Fu
Sometimes wuxia campaigns are a tough sell. It is likely that a number of players in your group are not familiar with the wuxia genre or have misconceptions about it. I observed that the more they learn and understand the key assumptions behind most of the martial arts and magic, the more comfortable they get with it (it just becomes less random to them). They also start to notice wuxia more. Players who might in the past have glanced over martial arts titles at Target or Netflix, mention to me that they notice and check them out.
Real World Martial Arts Knowledge Doesn't Always Help
I used to be very involved in martial arts and that was my biggest impediment to running a good martial arts heavy campaign. There was a gulf between me and my players, because I was thinking in terms of real-world martial arts and they just wanted the fun stuff they encountered in the movies. When I stopped worrying about real martial arts, is when things improved for me. That may not be everyone else's experience but it was mine.
You Can Run Them the Same as Your Other Games
Wuxia and similar subgenera are different from standard fantasy, but you can still bring all the basic elements of an RPG adventure to the table. Dungeons work fine in a wuxia setting, and you'll find plenty of inspiration for them in movies and shows like versions of Condor Heroes, Dragon Swamp, A Chinese Odyssey, and The Bride with White Hair. Wilderness exploration is a perfect fit. Finding secret manuals or artifacts are an easy McGuffin to fit into a dungeon adventure. Mysteries and investigations work well too. So does political intrigue. If you are more interested in combat and tactics, for obvious reasons it is a good match but you can always take a more cinematic approach here. It is going to be different in a lot of ways from a standard game. Most of the tools and adventure structures GMs are familiar with work just fine though.
There are elements specific to the genre that afford interesting adventure and conflict opportunities. Martial Sects are a noteworthy example. How sects are handled really shapes a campaign. It opens to the door to politics and intrigue and pits adventuring parties against potential rivals or competitors. That players are often connected to a particular sect creates interesting complications (especially if members of the party are from different groups).
You Need to Get Creative with Weapons and Techniques
This is somewhat specific to the system I've been using and to similar approaches (where techniques are individual abilities), but there is an escalation of Kung Fu Techniques that adds a lot to play. A common thing you see in the movies is a hero encounters an unbeatable move and has to figure a counter or way around it. I look at the established Kung Fu Technique list in the game as a starting point, and assume that martial arts are always evolving in the setting as masters try to outdo each other's techniques. The Rising Phoenix Strike may be the most feared technique at the moment, but in a few years another great martial expert might figure out its weakness and outdo the Phoenix Sect. As a GM I am constantly creating new techniques as a response to NPCs getting beat, going back to their sect and trying to formulate a reply to the Player Character's astonishing Kung Fu. By the same token, players do this as well.
Wuxia Series and other Chinese Dramas are a Big Inspiration
Movies are are obviously very important sources of inspiration. I've based entire adventures on films like Come Drink with Me or The Dragon Chronicles (The Maidens of Heavenly Mountain). However wuxia and mythic series are much longer and can go into greater detail. I find watching those really helps with getting cool adventure ideas. There are a lot of classic shows available online, and new ones are coming out fairly regularly.
Fundamentally, it is about the Characters
When I think of the wuxia genre, the thing that pops into my mind are the stark characters. Sometimes they are drawn so starkly, it puts them on a wonderful collision course with doom. For me, this is what drives most of my campaigns on and on: the PCs, the NPCs, the sects, the conflicts and schemes that flow from them. This doesn't mean adventure structures are all about characters interacting; it just means it is the fuel. All kinds of adventures can arise from this (everything from wilderness exploration to dungeon crawls and investigations).