According to a recent post by the PlayStation Blog, the PS Vita version of Borderlands 2 will be limited to two-player online co-op. Apparently four-player co-op was originally planned, but somewhere along the line a decision was made to remove it:
Borderlands 2 is a blast when you’re flying solo, but the PS Vita version also includes support for two-player online co-op play between two PS Vita owners. We checked in with the SCEA Third Party Production team, who confirmed that while they strived to include four-player co-op in the game, they made a decision late in their development cycle to focus on providing the best two-player-only co-op experience possible. As a result, the maximum co-operative player count for Borderlands 2 on PS Vita is capped at two.
Whether it was technology limitations with the PS Vita, time constraints, or something else that ended up being the reason for its removal, this is disappointing news for those that were looking forward to four-player portable co-op action. However if it couldn’t be done right, best to just get rid of it than include it and have it be a mess.
Borderlands 2 for the PS Vita will be released on May 6th.