CWK weapons mystery, where is the end of storyline?

Surely, there are. Who knows, maybe they will implement the other quests later? Something like Ellin Forest, which doesn't have any quest currently, but could get some in the future..

Also, do you think there will be more quests with Raven Ninjas?

I hope so. There weren't many quests with them. What about Lukan? Everyone forgot about him, too. He got transported from the past to the time period we are now, and he just remember seeing a big light, then nothing. Then, he found himself in the time period we are now.

Many things yet have to be explained, don't they?

It's just the end of the Crimsonwood chapter, not the end of Masteria. And, as was the case with NLC and even, to some extent, the Mansion, these people are going to continue to play an important role in what happens. I'm sure the Raven Ninjas will have something to say in regards to the Dragon Ninjas; these Dragon Ninjas are a corrupt and degenerate splinter group off the same root as them, of course they're going to have some honor to reclaim by defeating them. If the Watchtower/Isle of Vigilance does become an area, then the Raven Ninjas will no doubt be involved with them as well. Since Lukan actually fought the Krakians, and he's the only person alive to have done so, it wouldn't be a surprise to see him pop up in relation to Krakia as well.