Flight time
Ask yourself what your area of mapping is. Longer flight times let you reach and map the largest or the most remote territories. Moreover, greater endurance allows for maximizing the operational efficiency of every single flight. It keeps the cameras in the air for long periods of time, letting you collect more pictures without returning to base.
Payload capacity
Payload capacity is the ability to carry different sensors. Consider how much detail and coverage you need and what sensors would fulfil those needs. Then, look at whether the drone can carry the weight of the camera of your choice and how easily the sensors can be integrated. If you need more cameras, they need to be easy to swap and deploy.
Software options
Drone software includes GPS systems, planning, and flight software. Currently, there are GPS systems up to 1 cm commercially available. Planning and flights are becoming increasingly autonomous to bring ease of use to your operations. You need not worry about flight planning, pre-flight checks or navigate it manually if you make sure the software does so autonomously.