@Khmer, I agree, the RNG used is WoW does not seem to be the greatest. However, it affects us all the same.
I also agree with @Krom 's assessment of Melee heroes,
Perhaps you have ascended beyond the true capability of your heroes. This may explain why you are struggling of late. For example, my trophy count is a few hundred lower than yours despite my heroes being better equipped. (Unfortunately I am experiencing a endless leaderboard loading glitch which is preventing me from precisely comparing our counts.) I have a slight advantage in most Battle Mode matches which makes my current leaderboard placement quite comfortable. Perhaps you may find the app more relaxing and enjoyable if you descend a few rungs on the ladder.