I do not personally find QPs to be terribly useful in a mindgate deck, though I know lots of people disagree with me on that. I prefer to just get my quanta for the opponent's cards by mindgating pillars/etc and just hope they don't have anything terribly important that's fueled by the mark.
Regarding the steals, I'd kinda recommend swapping to a dark mark and just fueling the steals from the mark/pends. Don't even really need that many pends as you don't need to be able to play the steals that quickly.
In order to get down to 30 cards to be able to chain dim shields more effectively, I'd recommend dropping the immortals in favor of ~2 phase dragons.
A couple lightnings are pretty excellent in decks like this IMO.