While Gearbox announced they were "cautiously optimistic" over Battleborn's release, which was on track to outsell Borderlands, it appears as though things might not be going very well for the game.
The game released a little over two weeks ago and it has already seen a reduction in price. Instead of costing $60, you can currently grab the game at a $20 discount for $40. While this doesn't outright show that the game has been suffering issues, the Steam Database has revealed that there aren't that many players playing the newly released title.
Since May 12th, Borderlands 2 – Gearbox's four year old shooter, has outperformed Battleborn in the amount on players during peak gameplay. Daily, there are around 3,000 more players in Borderlands than Battleborn. As of yesterday, May 23rd Borderlands 2 had 8,058 players, while Battleborn saw 4,343 players at its peak.
This might not outright prove Gearbox is having a tough time with Battleborn, but it certainly does suggest it. In addition to that, Battleborn's competitor Overwatch released today.