The respawn time in Gambit or solo events is just too long. One of the medal requirements for Gambit (Rapid Payback) required a player to defeat the guardian that killed them after reviving but this is impossible given that it takes 8 to 10 seconds to respawn and when one returns it is on the opposite side of the map by which time the invader has left. In solo missions (or just roaming) the is zero reason for a countdown before one can respawn.