earth is out because its meant to tank not hit, water is meant to support not hit, for because of point 3 those 2 mains are out.

which leaves wind fire lightning:
1) wind - has clones to eat extra damage, fire - has cc to prevent damage, lightning - has life steal to recover lost health

2)all 3 are dps meant for hurting enemies not stalling out

3)all have a powerful aoe myst, a support myst, and another myst for damage, fires chases dont do much damage alone but give effects for extra damage while wind/lightning have high damage chases

4)no main MUST use either of those nin

5)with lightning u could do a swordsman team which is immune to cc for 2 rounds, that lets u burst hard the first 2 rounds for a good lead,
wind could do *l wind team
fire ur already using so...