[feuerdog]

I'd look at it two ways....

A. A multi-purpose/all-purpose squad/platoon that is structured for as many possible generic eventualities as possible.

B. A mission specific squad/platoon that is assembled with completing a focused objective.

Which would I use? Both. Depending on the situation, and leaderships best judgement of chance of success.

For generic organization, look at the compostions possible in US Navy SEAL teams, or Ranger SFODA teams.
They are designed to be flexible multi-mission capable customized teams.

In Planetside i'd look primarily for specific minimum requirements to be multi-mission capable.
Assuming the typical 3 squads to a platoon; each squad would....

1. Be self/bulk(sunderer/galaxy) transportable by either land or air, or both.
2. Have at least one HA or Max unit focused on anti-infantry.
3. Have at least one improved cert Medic with group healing/revive.
4. Have at least one improved cert Engineer with repair/construction.
5. Have at least one improved cert Infiltrator with hacking/stealth.
6. Have at least one improved cert LA, with squad spawn/waypoints.
7. Have at least one anti-ground vehicle weapon.
8. Have at least one guided anti-air vehicle weapon.

To further improve on this composition, each player would need:
1. Cross-certification into at least one other improved primary role.
2. Have some level of self-heal/self repair functionality.

The tricky part, aside from not knowing what PS2 has in store for us, is to what level of cert specialization will be considered improved enough to be adequate.

As for vehicles, I don't see them as a core of organization, but more of a supporting role.
Since anyone can essentially spawn anything, agin it becomes a matter of bringing the right tool for the job.
To further improve the squad compositon again, each squad would have:
1. One improved Bomber/Fighter/Transport air cert.
1. One improved Tank/Buggy/Transport ground cert.

Further specialization of a non-generic nature would be hard to define, but I wouldn't rule out squads of:
1. Infiltrators for guerilla warfare.
2. Armor only players.
3. Air only players.
4. MAX only.
5. Light Assault only.
6. Etc
It would depend on the need of the mission at hand.

One thing is for sure though, the braod possibilities that PS2 presents us with means that almost any custom composition is possible as long as the resources are there to support it.