I've only been playing for about 1 season, so I don't know what it was like before, but I'm pretty satisfied with the rewards I'm seeing in Bronze I. I would love to get 400+ DEC for one battle like you show in that screenshot, but my collection power is barely enough to make Bronze I, so I'll be patient!
From what I've heard, the DEC rewards were changed to discourage bots; unfortunately that means also making things harder for novices, but I understand the need to address the bot situation.
Yes, Catotune, I believe you're correct that it's to slow down the bots a bit, or force them to get smarter... hahaha :) I believe the DEC is still getting corrected, so people in Bronze 1 were seeing better results. Let's hope that's the case, and then it's wins for all of us who have put effort and some investment into the game! ;) Thank you so much for reading and commenting! :)