A bit to explain what's the point of seasons in arpgs: basically a season gets a few new changes/mechanics that are supposed to change the experience. Everyone starts fresh, and the seasons theme is what makes it different. It also affects the balance of the game, because it means all the new mechanics affect you from early game - instead of balancing mechanics around uber late game grinders.
With living games, you either do vertical progression, or horizontal progression, or you do seasons and wipe the board clean.

As a casual-ish player I like seasons because everyone is expected to run around sub-optimal setups and the game is balanced around that. Getting stronger is kinda the point. Then once I reach a certain point where my setup is "good enough" I can call it for the season. I've "completed" the season, and people who want to push further can keep going and keep perfecting their builds until the season is over.

I'm d3 I've played every 2/3 seasons, each time a DH build, and it was a fresh experience each time.