The req level costs of all of the wasps needs to be increased by 1. Currently the wasps sitting at 3, 4, and 5 makes them extremely overpowered for their cost. At the moment the current req level between the vehicle cost and the req cost of the counter is balanced across the board except for the warp. The top counters for vehicles include plasma pistols (req 3/4), railguns (4/5), and splasers (5/6/7). Before wasps, these were all available for cheaper than the strong vehicles they are used to counter (Wraiths, Scorpions, Banshees, Phaetons.) Now that wasps have been introduced there is no real proper counter to them at the appropriate req level. This is due to the counters being at the same req cost or more, which causes heavy snowballing to the team that is able to get wasps out first when the other team doesn't have any counters available. Currently the only real counter to wasps in the early game when you're down a req level is the standard chaingun turret, which isn't the proper counter that hits the rest of the vehicles. Even if the teams are equally equipped with reqs, there are sill very limited counters. These would include the plasma pistol, sword needler warthog, getting lucky with a level 3 random weapon, or pulling out a wasp of your own.
If the req cost of the wasp was raised 1 level, a trailing team would still be low on reqs to counter it, but the time to counter it comes slightly later in the game. This gives the opportunity for the losing team to still gain kills on players and AI in order to get their req level up. With a req 4 standard wasp an equally reqd team will have plenty more options in order to take it down. These would primarily be railguns, and the stronger voids tear plasma pistol; you can also take a chance with the 4 cost random weapon. This also puts the stronger wasps better inline with the harder hitting counters and makes them more reasonably countered by other vehicles.
Overall the current balance of the current reqs in warzone is pretty solid. The only other changes I feel could be needed is a bit of a modification to some of the DMR variants that require req 8 that really should cost 7 (variants that simply have attachments such as stabilizer, silencer, etc.)