Creature Swap and Majestic Mech Ohka should definitely be added then...
Ohka rams itself to a lot of things. It's friendly with creature swap for you to kill something, steal something then it blows itself up while drain isn't out. When it's out, 2400 beatstick of doom.
Rat still works with drain like all recruiters, and it can pull exiled force which is never bad.
Not sure why you need nimble momonga then... it does make a wall but what for? not like skill drain is meant to use tributes. True that they pay for some cost, but more LP just means you're paying for solemn more. I don't think LP is an issue if you run solemn, which you must to protect skill drain. Solemn and Nimble Momonga are counter productive, and I like Solemn more. If you want a wall, Crush Card Virus with Giant Germ.
If earth is not in your favor, I'll personally pick tomato with newdoria and giant germ. As much as it's old, unoriginal, it works with Crush Card Virus darn well. Newdoria is a weaker Exiled Force in a sense but you can pull him out to def. All of them works with sangan and Creature Swap of course.
If you want more virus for the heck of it, giant orc and fusiler are both compatible for DDV as well. If you aren't using virus, then generally GEAF or even GAF+RotA serves a better purpose than Giant Orc.
D. D. Crow or Necrovalley can be teched to stop graveyard frenzy in today's metagame. Dasher is still painful even though Disc Commander is stopped by pulling out 2800 beatsticks, which beats most of your beatsticks. Zombies we all know about them.
Now for the spells... shield crash/NoC have to be there since you're aggro and wants to get rid of the threats for obvious reasons. Premature Burial and Book of Moon are nice (book of moon can set fusiler to full attack without Skill Drain). Brain Control is still nice as end game mechanism to remove a wall and attack, even though you rarely rarely ever tribute. Enemy controller is another option to force people to attack mode. Keep Swords there to minor stall while you are still waiting for Skill Drain.
I'll say avoid smashing ground and fissure though... you probably have the attack power to run over plenty of things to rely on them.
As much as it sounds crazy, heavy storm and MST should still be in here. Heavy Storm may kill your own drain, but then you should learn to time when to use it so you win in that turn. You may get rid of drain, but if your monsters are already on the field (Ohka, Fusiler, etc), they really don't lose anything if you can ensure that you win in that round, or within 1-2 rounds. MST is really needed to help with blasting the back row, and to stop
Traps... 3 solemn asap. Flexible and protect skill drain which you desperately need to do. Include the viruses if you decide to use them. Mirror Force, Torrential and Call of the Haunted (Call is limited to 1 by the way) are givens. Dark Bribe may be considered as well (I personally say 2.)
Note: if this is 2008, I'll say either go with the virus combos with tomato, or go with yomi ship, grizzly and deep diver (deep diver is the 2008 card promo which should be in the game itself)