Wraiths are a ridiculously weak unit, even with a Destroyer Lord supporting them and they are still poor, due to their lack of unit size and power weapons. Drop them.
Beef up the Immortals to 10. Your lord is not built to be competitive, if he is on foot he should be holding a Resurrection Orb, or he's just there to make your army valid.
Give him the Orb to support your army or group him with the Immortals, with Veil of Darkness and Solar Pulse, and jump around the board irraitating with outflanking maneuvers and contesting objectives.
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If you're going for a Destroyer wing-based army, at 1500pts it can be hard, the tactic works best in with 2000pts.
Mandatory two squads of Warriors.
Get a Lord with Veil and the Solar Pulse, with a full squad of 10 Immortals. Use this as a distraction unit, something to be threatening and to take the attention away from your Destroyers.
Have three groups of 3 Destroyers, and keep them close to each other for
WBB. This brings points too 1270. Then add a Monolith to support your troops, you'll be 5pts over, but most people wont mind about the low number.
It's a hard tactic to pull off in a low point game, but I wish you success.
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An army I use at 1500 is:
The Deceiver - 300
10 Warriors - 180
10 Warriors - 180
4 Destroyers - 200
4 Destroyers - 200
4 Destroyers - 200
Monolith - 235 = 1495
I've had alot of success with it to date. Hide the Warriors in the back [always within 18" of the Monolith] while moving forward with the Deceiver and Monolith. Destroyers can munch through anything and in the masses are extremely deadly.
I hope all that helped