Onix, you raise an interesting point and the answer is a rather disappointing 'depends'.
It depends on how the group wants to play it and the style of the GM. You don't need one of each, the GM has plenty of scope to tailor activities to the talents of the team.
You can have an entire group of security that's armed to the teeth. The GM still needs to keep them all busy and interested. With characters using different skeletons, they fill different roles and it is easier for them to have a unique place in the team and have something to do - even HR! I'd try and put one technical person in the team, all the others can be doubled up as much as you like!
Smaller groups might benefit from an NPC to fill the role no-one else is interested in, which I mention in the GM section.