Yes to all those question lol. The lance has a good L1+Triangle. Better if you jump in the air too. It launches players in the air so you can combo them. The L1+Square is awesome for when people are close to the edge of a map because it pushes them off. And, if for some reason they survive, the L1+Square attack slows them down.
I honestly think it depends on your play style. I was having the same debate. The War armor has higher elemental damage which is awesome I think if ya wonna put some hurt down on them with Poseidon. At the Maul and go to town. But I am more a tank spec. I choose him because of the high damage he can withstand. I went with the battle armor for survivability. And I think I also went spear over lance for the same reason. Lance shoots a jet of water out the tip, and does some kind of healing circle thing. cool, but I like the ice power of the spear. Kraken Armor only good I think for it's cooldown. Not really worth it though I don't think. but again in all fairness I haven't used the War armor much and built it up so I could be wrong.
I too am of the opinion it is completely dependent on your play style. Do you have a team to run with and provide support like a white mage ? If so then elemental is very good for support but not so much for defense. If not then the healing ability is underused and you would need to play it by your teammates and how they are working with you in that game. Some even without mics stick together in a group of 2-4 automatically. If not then pick something that you like the attack of and can use well. Then pick your armor to suit the weapon and playstyle that is successful for you.
Can you give an idea of your playstyle and the weapon you like to use so we might be able to give more than just generals?