Kakashi is good, when he negates, another of your ninjas gets his effect after he is discarded through Inherit. Fire is getting some interesting combos so far, although I hope we get a lot more double and triple element cards, otherwise we're going back towards mono element decks?!
While they will probably continue, Tri elements probably won't be usev as much simply because they make the sets in a block so this is like the first set of yhe new block I think and 25 was the end of last block.
Considering the effect can then be transferred and thus not lost, and plenty of wrecking jutsus that turn games around (Flames, Rasengan, Mind Transfer, etc.) are staying, I'd say the cost is pretty decent. Not to good sure, but not horrible.