I don't mind playing the campaign, I'm looking to play the game again to have a fun experience and not min/max like crazy. Should I beat the campaign first so that I can start a character with the new season in adventure mode? Or is it fine to just do a season in campaign mode?

I've read that it's better to do a season on adventure mode rather than campaign mode though, so that's left me wondering. I'm going to start a new character, but since I'm doing that anyway I figure I'll just wait for the new season, which should start within the next month or so, I believe. I also have some idea about seasons from my brother and a bit of reading about it. By now, I've read enough good things about how much the game has changed and RoS that I think I'm going to get RoS and give the game another try. I beat the story the first time through and really didn't enjoy the game near as much as I expected, so I stopped playing and haven't played since. So I haven't played Diablo 3 basically since launch.

Rebirth in diablo 3