Because there is a character wipe with the new season, if I'm close to finishing the campaign, should I just focus on that and get all the altars, and avoid everything else? I don't see much point leveling up and planning out my character build and obsessing over equipment if it's all going away in a week.
Seriously, why are there so many people who believe their character gets wiped? That's not going to be the case, your character will stay, but you can't play the season content with it, you have to create a new one.
Clearing campaign and getting all the statues is the right thing to do because the statues carry over to every new character and you can skip the campaign for the season character. All this is only relevant if you want to play the season. In that case I'd recommend to read some of the guides - on maxroll for example
I don't know how much experience you have with Diablo games, but don't worry.
When a season kicks in, you will have to create a new character, your old chars won't be affected, they just won't be seasonal characters.
The game will have a another "realm/world" that will be for seasons, and the "Eternal" realm/world, this is the one where your current characters will remain.
Check when you log in the game. That this is the name of the current world you are playing.
Even when playing a seasonal character you will be able to get to your old one and finish things up with him. This will not affect and/or progress anything on the season achelievments/mission thought.
On D3 we have something called rebirth where you just reset a normal char into a seasonal one, this was nice mainly because some players like to keep track of the amount played with the character. And to save a character slot.
Nothing to worry, keep playing and unlocking everything you can.
My tips is to finish the campaign, so you will be able to junp directly into the seasonal content and open up the map, map, renown and Lilith statues progressions will be shared with the seasonal character.
Short answer: your character wont be wiped and you can continue to play with them. Focus on finishing campaign, map explored 100%, and all altars visited before participating in Season 1.
Long answer: to participate in seasonal content, you will need to create a new character. Assuming you have already completed the campaign once before, that new character has the option to skip the campaign and get right into the seasonal content. Additionally, progress you’ve made towards specifically the altars of Lilith and the map fog of war will carry over. Nothing else will, including additional renown.
Your main character will be forever playable in the “Eternal” realm, which is to say everything the game has right now. But generally people enjoy starting over every season and checking out new and fun experiences.