I would say most of the problems of Jade Empire were the same as most of the problems in Mass Effect, and the same problems in most 'action-RPG's'of this type, that is that they fall between two camps. One is the deep RPG of Morrowind or Vampire Bloodlines, where because you can be so many characters you need a truly thought out world. In a simple example, you need a house that can be attacked from the front (warrior), snuck in from the back (thief), the ability to talk yourself in (speech skill) or hack your way through. All of these having to be fun. In action-RPG's you pretty much have the warrior character whether you want to or not. So whether in Jade Empire of Mass Effect, the fighting options were pretty linear in nature.
A true roleplaying game tends to have a sandbox world, an action game tends to be much more linear and structured. So when we get these two styles together, something jars.
The media, in it's supine position doesn't want see this and is therefore quite happy to still call these more action orientated games 'RPG's', when by historical standards they blatantly aren't. It has led gamers and the media to start calling games like STALKER RPG's, and any game that gives you an inventory of different armour and weapons! Mass Effect gave you in many ways an adventure game for the first 30% then a mixture of adventure and third person shooting, culminating in mostly shooting . Jade Empire, in it's own way, gave you a very light RPG with a heavy dose of arcade hand-to-hand combat. Both failed in many ways as a true RPG, and each were only slightly elevated by the action elements.
You could say that PC gaming is dying by the death of a 1,000 cuts. One was maybe for each genre lost, maybe another was going from Big Box to DVD case, and maybe another is the trend to have 'action; in every game now. Whether third or first person, with weapons or hands, with technology or magic, and anything that demands use of the brain a little more dropped. We are told resource gathering, base building, step-time, supply lines etc are now 'boring; in RTS games, leading to an RTS like World in Conflict that plays like a fast paced FPS! We get trends like Oblivion being a dumbed down Morrowind, Fallout 3 being a dumbed down Fallout 2 and GTA IV having much fewer RPG elements than San Andreas.
All these trends point toward more and more action games, and fewer adventure, RPG or simulation games, it points toward ever more shallow games with less gameplay (2009's Dead Space and Mirror's Edge (PC) both had under 12 hours of gameplay!) and dumber storylines and characters. In short, it's points towards ever lower AAA PC and video game sales and further growing interest in older games, whether through X-Box Live, Sony LIVE or through 10 million plus DOSBox downloads recently announced.
Times they are a-changing. When Bioware went from their Baldur's Gate's and Neverwinter Night's to their Jade Empire's and Mass Effects, a change was signalled. An these changes are now coming home to roost. First with the PC, and soon with the hardcore console machines 360 and PS3. There's a reason the Wii and DS are sweeping all before them. Hardcore isn't hardcore any more. Jade Empire wasn't hardcore anything.