'Eavy Metal: 2K Ork Meka

[Waaaghpower]

So, in spirit of my Themed List craze of late, here's a proposed Big Tank list that I'm considering running. It combines Battlewagon Bash themes with hints of Kan Wall, in the spirit of a Mek-run army (or at least sub army underneath a Bigga Boss.)

HQ:
Big Mek (Kustom Force Field, Grot Oiler) - 90
Big Mek (Shokk Attack Gun) - 95

Elites:
Burna Boys (10 Boys, 1 Mek) - 165
Lootas (15 Lootas) -225
Meganobz (5 Meganobz) - 200
       Trukk Transport (Big Shoota) - 35
Troops:
Deff Dread (2 Skorchas) - 85
Deff Dread (2 Skorchas) - 85
Boyz (19 Boys, 1 Nob w/ Power Klaw, Bosspole) - 160
'Ard Boys (17 Boys, 1 Nob w/ Power Klaw) - 235

Fast Attack:
Dakkajet (Fighta Ace, Extra Soopa Shoota, Red Paint Job) - 135

Heavy Support:
Battlewagon (Deff Rolla, Kannon, 4 Big Shootas, Grot Riggers, Armor Plates) - 155
Battlewagon (Deff Rolla, Kannon, 4 Big Shootas, Grot Riggers, Armor Plates) - 155
Battlewagon (Kannon, 4 Big Shootas, Killkannon, Armor Plates, Grot Riggers)

Total: 2000


The plan is to put both boys units in Deff Rolla wagons, put my Burnas and the KFF mek in the Killwaggon, and then roll forward and kick ass. The Force Field protects from unwanted shooting,  (Ideally it will be night fighting on turn one, too, which would be even better. I always roll on command traits just to try and make sure it's night,) and between 4 Battlewagons, I have a nearly unstoppable wave of armor. Even if a couple of them are popped, I've still got large amounts of firepower ready to go. And, meanwhile, I've got a flamer filled Dakka Wagon burning holes in his men and 15 lootas with a SAG melting from a long ways away.
So, what weak points am I neglecting to shore up? How would you crack this list?