the last boss in ramparts is easymode with shamans. Park them on the bridge, not so far they can't DPS anyone at the front of the bridge though. You don't need to do any special tricks, just kill the 2 guys with your pally tank, kill the orc boss, then kill the dragon.

Some very important things though:

1. Shamans MUST ALWAYS HAVE GROUNDING TOTEMS DOWN. They eat the fireballs the dragon throws, without this your group will die fast. Every 20 seconds I press the key that drops grounding on all my shamans.
2. If you can, try to keep your pally in range of the grounding totems (at max). Helps a lot with damage.
3. Heal the paladin when he drops to 60% or lower.
4. Make sure you "spin" the dragon whenever he drops a fire gumball on the ground. I just spin between 3 o'clock and 6 o'clock, alternating between the two (sometimes 12 o'clock). Don't turn him when he breathes fire, only when there is a big fire ball on the ground next/on top of you.

The most important thing is grounding totems, if you do it right your shamans will take 0 damage the entire fight making it easymode. Then you just have to keep the paladin alive, being good about moving out of fires is key here. I put on my FR aura and 1-2 pieces of epic fire resist gear to help as well, with my 70 pally I can do the fight without a single heal.

Its a lot, lot, lot harder without grounding totem(s), since the DPS group will eat fireballs and suck up massive mana from the healer (who will also need heals).