Well, to be fair, this is a game in development. None of the current or past versions ever promised that it will forever be stable from Alpha 0.1 til the end. So a hard reset is something that players should've expected at some point, especially when we add new features.
I understand your bitterness, since not everyone is keen on replaying the game, but ultimately, it's your decision. Who knows, you might come back some day, and I hope you'll enjoy a full experience then.
But I will not backtrack on this update, as the new Rival is tied to the story and even if I removed the Level Cap implementation, you will still need to reset or else the game won't play correctly with the new Rival's introduction anyway.
Best of luck, it is what it is.