You have several good points but i'm going to have to counter them.
1. I don't play BA, I'm a solid Vanilla Marine.
2. I frown upon deep striking. The main part is that they are stuck out in the open like sitting ducks. And on top of that they can't assault afterwards so yeah.
3. The Vanguard veterans have no Jump packs so can't deep strike
4. Libby is going with Vanguards to cause some havoc with re-rolling sucessful invunerables
5. I Expect someone to pull a good Tank out of their ass (allowing total of all armour 35 so a vindicator will cause some havoc) therefore melta is there to prevent that
6. Plasma Pistol is there because of WYSIWYG
7. The point for the Vanguards is that they pump out as many Ignoring armour save attacks as possible. I prefer not to give one a powerfist and on top of that, if i need to instant death something, I'll use the meltas.
8. The board is quite small. 24" is Fine for the board.
9. No point in giving the libby a Melta bomb, he still has krak grenades in case of dread or such trying to tie him up and he isn't going tank hunting.
Not trying to offend you. (oh, and my opponet might not be a he!)
Good try though!