If the makers of the game are reading this, can I just make a request for the sequel? In the next game, can you offer a single-player mode? This game was a for-sure buy for me until I learned it was multiplayer only. I tend to be a solitary gamer who plays for the campaign and story, so I was bummed to find out there was no single player mode to a game I really wanted to get my hands on!
Not sure how great a single player would be. All it is basically is borderlands and team fortress 2. As fun as borderlands is the single player got pretty boring about halfway through.
Personally, I don't feel this game is designed for single player. Sure, it might include a training mode but that's as close to single player that you'll get aside from humans vs bots matches.
This is a multiplayer game simply put. It's designed primarily to be played with other people. Dota 2 or League of Legends don't have a story mode. Neither does Team Fortress 2 really. These types of genres aren't meant to have a single player mode. There's other games for such things.
If you want to remain a solitary gamer in this specific game, you can just do so vs bots or do the training mode. If that's not enough for you, there's other games more fitting, no offense.
Even as a solo player it's real easy to get into the flow of every game. The game breaks down every team whether its well balanced and if you need to change it up. Just pick someone you like and practice getting good with one or two characters. You can hit the range or train against bots to get the feel and movement down. It's a lot of fun.
Doubtful there'll be a sequal since this is Blizzard, it'll go the way of TF2 and be continuously improved and updated for who knows how long. Best we can hope for is story DLC or a movie.