The death ray bug is only a visual bug. It still does damage to anything in it's path.
Power Transfer is more of a utility spell with damage on it then a damage spell with utility on it. It has a small range since Viktor is a close range mage- he's suppose to get a shield off, toss down his other spells, then back for his CD's. Unless you have a LOT of AP and can actually blow someone up in one rotation, you're suppose to go 2-3 rounds with your enemy 1v1, or support your team with AoE burn, AoE slow/stun, and an AoE silence/damage.
Gravity Field I agree with 100%. They either need to make the Augments better overall to make Augment: Death not the only viable one for damage purposes, or just increase the cast range of Gravity Field