The guestion is in the description of the deck @ http://deckbox.org/sets/465930 I try having fun re-working pre-con decks. I seen this one and wanted to see how other people would change it.
No sense retyping everything. :)
http://deckbox.org/forum/viewtopic.php?id=12209
A couple others weighed in also. The TLDR version is.
Lands - get the nonbasics or it won't work, it's a multi colored deck
Colors - stick to WG with a splash of red.
Ramp - The best slivers cost 4,5,6 you should put in elves to ramp to those asap, Avacyn's pilgrims/Elvish Mystics (manasweft really isn't effective ramp. You'd want to be able to play a 3 drop turn 2 to keep up with other aggro decks)
Removal - Deck needs utility to work, Selesnya Charm, o-ring. Red provides shock, pillar, searing spear, mizzium mortars.