This is probably one of my favorite squads since Vader is my favorite character.

Darth Vader, Imperial Commander
Lando, Hero of Tanaab
General Veers
Admiral piett
Mas Amedda
15 Stormtroopers

I have a very similar build to this except without Veers. (I figure with so many attackers, you can take out the fodder pretty quickly) The only other difference is to not have so many basic Stormtroopers and throw in some Elites. You only have a base +4 and conditional +8 attack. With the Elites, you have a +8 base and +12 conditional. I think a good mix would serve you well. You could maybe even have a few Elite Snowtroopers. +6 attack and +1 to defense, but +10 HP as well, so it can take two 20 damage hits if you have to move it to open a door and leave it vulnerable or something.