Im i the only one to find the concept of opportunity useless and make the game to heavy? 

Fortunes and Winds, guys. Fortunes and Winds.
R&K is almost right out because I don't think FFG bought the R&K rights when they bought the L5R IP. Did they? I might be wrong on that.
I want to relate an experience about linking your dice experience to the game itself. Once upon a time, it was a lazy Saturday and it turned out it was also Free RPG Day. On a whim I scooted down to the ol' Gamin' shop where people were demoing games. A larger but still kindly gentleman who very poignantly did NOT smell of gamer funk asked me if I wanted to try his game, which had a very tempting Star Wars logo on it.
"Can I be a Twi-lek?"
"Yeah, sure you ca-"
"I'm in."
This guy, whose name I have completely forgotten, led me through character creation which was pretty quick for Edge of the Empire and by the time I was done some other people had shown up and we were ready to get underway. But of course, first we had to learn the dice mechanic. Cue a box of multi colored dice in fairly original Trilogy reminiscent tones. These dice were different, though. While they had familiar shapes to an experienced gamer (which would have been new and different to a person just starting in role playing), they were covered in weird symbols that didn't correlate to Roman characters. In short, they looked like someone had smuggled them out of a Tatooine gambling house. When the system was explained, it actually seemed pretty easy to grasp and as a group we didn't even learn the real terms for the symbols. Throughout the game we counted up Explosions, bad guy triangles, and winged light-sabers. It was super fun and I was enthralled the whole time. Of course, it wasn't like being a super rich Twi-lek mafia scumbag wasn't helping though.
Anyway, my point is this. The Narrative Dice design, as applied to a Star Wars game, was infinitely appropriate because it took something different and a little bit alien and applied it to an alien world. In Star Wars, while a lot of people speak understandable Galactic Basic, the text is all different and weird and of course aliens speak a myriad of other languages that have to be subtitled. So alien dice are right at home and even enhance the experience of playing Star Wars. also, having a different metric whereby you measure success is indicative of an alien way of considering measurement, which is, once again, very Star Wars.
So I think that the Narrative System worked quite well for Star Wars.
I don't know how well it will work for other genres, like steampunk, or medieval fantasy because there are different paradigms there that I think the same mechanics may have difficulty meshing with. Genesys is in a difficult position trying to be everything for everyone. We've seen from even past editions of L5R that such a feat is Herculean indeed.
Anyway, it is my hope like some others have stated, that FFG L5R has a system that will mesh well with the themes of its world. Something that will make it deadly, but fantastic, and prone to a little bit of wispy ennui. And also Shuigenja explosions.
Fortunes and Winds, guys. Fortunes. And. Winds.