So today Deck Builder was acting funky (showing decks with no cards, a bunch of nulls) but was still functional, now for some reason entering Deck Builder causes iMTG to crash. On a possible related note, my jailbroken iPhone 3GS is also not letting me access Cydia or installed packages which started at the same time Deck Builder stopped working.
EDIT: Turns out it the jailbreak started working again after a hard reset, no such luck with Deck Builder though.
Any cases of crashing should be reported via in-app support channels, please. Help in Gathering is for functional help.