Well, technically speaking mobs are supposed to respawn based on how fast they are killed to avoid bottlenecking in high traffic areas. That said, it has it's limits. Ever play on a freshly opening server and see 30 people standing on Sarkoth's spawn point playing whack-a-scorpid lottery? Same thing here. Even at maximum spawn rates, things are going to be tight the first couple of days/weeks. Sorry, dem's da breaks.