The new ninja event, as expected from a new feature, has generated a lot of discussion. I believe both the community and SG have to take steps in order to find a good balance.
I see a lot of players complaining about how hard going through the tower is. Well, would you like every single challenge in the game to be a boring random tile-matchung exercise?
Think about it carefully. Remember the times you could not get through S2 hard and the satisfaction you get for getting stronger and beating all the stages. This is the same, think about the things you need to do in order to complete the event the next time around. Maybe level up more healers? You need them for war anyway. Or learn to compose teams better? Or even improve tile play?
Use this forum to learn more and do not expect everything to be just easy. Why play this game at all?
Of course, better rewards need to be awarded by the game in order to motivate players to complete the stages. This is already being talked about in various posts.
Chill out, next time you will get there. Get stronger and enjoy your progress.