Looking from a purely tpvp standpoint.
- Time Warp
- Tome of Courage
Time warp is that ultimate team fight skill, remember generally in Foefire the centre cap point will change once or twice a game. Which means capping it at the start generally gives a big advantage to your team. Most matches I play have an average of 5-10minutes where the graveyard is contested before it's finally captured, except when one time utilizes TW to a better extent.
Tome of Courage is another amazing team fight skill. Most teams will just focus cc on you, you can negate this by using Sanctuary/SYG/Hallowed Ground or allies assisting you (which they will be). Team full heal is just insane.
The AoE damage/condtions on this one are insane, not to mention the effect of mass poison and your super strong defence, with high hp and blind. This is a crazy skill and can definitely turn the tide of any sized battle. Especially funny when melee cannot physically hit you (and as the enemy it's keyboard smashingly annoying =D!)
Moa has a low success rate, it's good for taking out bunkers but if their allies are good enough at supporting he won't die anyway. They do retain dodge aswell which means they just wait till the illusionary leap is casted or magic bullet to dodge.