There are a couple variations that can be made with the free white/blue deck. The deck can be highly creature oriented or tactically crafty.
Cards that specialize in a theme (soldiers and rouges) should be culled out, since the deck would be hard pressed to carry any specific creature theme. Taking out Helm of Fortitude and Nimble Dagger right away. Keeping the efficient creatures, creature enchantments, and spells, the deck starts to take shape:
Obsidian Golem x3
Dauntless Soldier x3
Initiate Soldier x3
White Knight x2
Guided Strike x3
Holy Strength x3
Silence x1
Sentry Rogue X4
Swashbuckler x3
Aura Finesse x1
Inspiration x3
Time Ebb x3
Unsummon x3
With 5 spells to go, throw in some harder to cast flying creatures and try it out:
Thieving Magpie x3
Voidminstral x2
Variation example
Some of the less efficient creatures (Obsidian Golem and Sentry Rogue) can be switched out for more crafty cards (Tactical Advance and Surgical Precision) or better cards from the free booster.
Of course, this is just one deck idea and the deck can either be a blue deck with a few white cards thrown in or vice-verse.
Complete white/blue list