The trophy balancing change from version 651 has been reverted with a small game-server update. Attackers now again lose only around 25 trophies instead of 50 trophies.
Logically the change made sense but thanks to your feedback I realized that losing too many trophies with a single defeat feels really bad.
Instead, changes to the matchmaking algorithm are planned to improve the multiplayer match quality.
Thanks a lot for your feedback!