In an effort to try and keep the game fair, we run balancing tests before each new release. To avoid over-powering new heroes, or making them intentionally weak, we try and balance them as best as we can.
If you have feedback on how you think certain heroes should be changed, please let us know in the Feedback section of UserVoice: https://dragonsoul.uservoice.com/forums/303411-feedback-and-ideas
We love hearing from you! It's possible we made a mistake. But even if we didn't, it's still helpful hearing from players that something doesn't make sense.