No..your not missing anything. I hate EA Oceania for just that reason. All your best troops are water only.
I'm by no means an expert, but the few times I did play them, I had to ramp up my conjuration and construction. That way, you summon up some armies that can compliment your pitiful lack of land troops (Sea King Court is a nice one) and forge some fish amulets so your more powerful underwater only mages and bishops can go on land.
That's pretty much all I can tell ya. Maybe someone with more knowledge will come along.