Do I have enough threats?

I just got crushed in a 1500 point battle with necrons. By turn 3 I was basically tabled. He ran triple annihilation barges. Those things WILL take out a DE vehicle a turn, if they can shoot at all. They can even get away with jinking every turn because snap-firing doesn't affect their damage output very much. Anyway I was wondering if it is even possible for me to build a competent list with the models that I have. I dislike the idea of beast-pack lists as a personal preference.

So here's my collection:

1 Archon
1 Succubus
1 Haemonculus
20 Kaballite Warriors (I've modeled 8 with blasters and usually run them as trueborn)
23 Wyches
10 Old-Model Mandrakes, which could in a pinch be used as wyches, mandrakes, or wracks
5 Incubi
4 Raiders
2 Ravagers
2 Venoms (Double Splinter Cannons of course)
1 Razorwing

I'm also eye-ing a 16 model old-style warrior box on eBay

So, my question is: Without adding more models, how can I make the most competitive list for 1500 points? Many thanks in advance  

Did you take Night Shields? Necron suffer from a 24" range on their weapons. I find cutting that down to 18" gives us a huge edge. Now your warrior squads are limited options with wysiwyg models. Now if you want to get up in face. Wyches/bloodbrides with Haywires will kill those vehicles.

What was your list last time?

Last time my list was

Sliscus - 150

9 Trueborn with shardcarbines (Sliscus embarked) - 153

Raider with flickerfield - 70

10 Trueborn with 6 shardcarbines and 4 blasters - 210

Raider with flickerfield and dissie - 70

5 wyches with haywire - 60

Raider - 60

5 wyches with haywire - 60

Raider - 60

5 wyches with haywire - 60

Splinter cannon Venom - 65

5 wyches with haywire - 60

Splinter cannon Venom - 65

2 Ravagers - 230 (115 each)

Razorwing jetfighter (lances) (it never got the chance to fire missiles) - 145

Total 1518 (I slightly miscalculated the points)

I am thinking of altering my list like so:

Archon: Shadowfield, Huskblade, Soul Trap, Combat Drugs, Phantasm Grenade Launcher - 170

5 Incubi - 110

Raider: Enhanced Aethersails, Torment Grenade Launchers - 70

4 Trueborn: 4 Blasters in a Venom with Splinter Cannons - 173

Same as previous - 173

10 Kabalite Warriors - 90

Raider: Nightshields, Flickerfield, Splinter racks - 90

5 Wyches: Haywire Grenades in Raider with Enhanced Aethersails - 125

Same as previous - 125

2 Ravagers with Flickerfields (or Nightshields should I be facing the hated 'crons!) - 230

1 Razorwing Jetfighter with Lances - 145

Total: 1501 (I can drop the Torment Grenade Launcher for 1496)

And thanks for the advice, I really appreciate it!