Mourkain Temple is a very straightforward scenario, which is both good and bad. The good part is that the lack of complexity generally results in a lot of action. The bad part is there is really only one way to win and thus little room for interesting, clever tactics.
There are really only two main ways to play this scenario. One is exciting and fun, the other is a pretty lame and repetitive. Unfortunately, the second is far more common. Sadly, it could all be remedied with a few improvements to the scenario.
Turtling or Hedgehogging
This is the standard strategy most people employ from both realms. It involves the carrier of the artifact immediately running back to their spawn location and hiding right underneath it. The carrier is then surrounded by members of his team, who (with the aid of ranged attackers from the spawn point) slaughter anyone who tries to kill the carrier.
Far too often, the only real challenge in Mourkain is getting the artifact first. The majority of scenarios are won by whoever gets it first. This is a real shame, because a lot of potential fun is wasted. The advantage to holding the artifact near your spawn point is enormous. Anyone on your team who dies is back in action really fast, whereas opponents who die must spend at least an extra minute or so before they get back. Ranged attackers, healers, and rezzers can often stay safely above the battle without even jumping down from their spawn point. This is especially true for order who tend to have more ranged DPS.
Order tends to turtle up behind a broken wall near their spawn point. Destruction tends to turtle up inside or behind a hut at theirs.
A team using the turtle strategy needs to remember that killing people is still the main source of points. If you are turtling but the other side out kills you significantly, they can still win. This happens sometimes when the carrier team is melee heavy and the other team is ranged DPS heavy. They can stand back and slaughter your "defenders" over and over. Any attempt to get at them in small numbers simply results in dead melees 1-99 feet away from the ranged DPS. This speaks to the huge imbalance in favor of ranged DPS in WAR, but that is a different issue.
Beating the Turtle
To beat the turtle, you need to either farm their defenders from range (as described above), or gather your entire team for a powerful attack on their carrier. If you wait a minute or two after the initial clash, you can get all of your respawns together and strike when the DoT damage from the artifact is starting to get heavy.
You will really have to fight effectively and focus fire if you hope to beat the turtle. The advantage to turtling is just enormously big in this scenario.
It might help to pick off a few stragglers or bored/aggressive members right before you make your big rush. This puts the numbers in your favorite for 1-30 seconds at least.