I'd need to double check, but Victory Rush was changed to 56% AP in Beta, yet I believe it was modified as, "Victory Rush damage has been reduced by approximately 17%," in 4.0.3a. That would imply that it is around 46.5% AP now--but interestingly the tooltip on Wowhead still shows 56% some time after 4.0.3a.
I would need to double-check this in-game to be certain.
Either way, Shield Slam is 60% + 2.8k base damage (ish) with a 110% multiplier when glyphed, yielding 66% AP + 3,057 damage.
Victory Rush has a 115% multiplier due to War Academy, yielding either 64.4% AP or 53.5% AP depending on what the real value is.
At high Vengeance levels, I guess we will be seeing Victory Rush become pretty strong. I suppose given that the static damage portion of Shield Slam will become less and less important over time, we may potentially see a shift in priorities here.
Right now, my hunch is probably that SnB still wins out (although Victory Rush would make a great 3rd GCD filler at high Vengeance) at the moment--but there may be a time where it flips around a bit and stops being a TPS loss and instead is a TPS gain. I will do some investigation into this.
The biggest issue with Victory Rush at lower gear levels is that without being included in SnB, it means lost opportunities for Shield Slam. However if Victory Rush closes in on Shield Slam in damage and has a higher proc rate from Devastate, some rotation of Shield Slam > Victory Rush > Devastate fishing (as Devastate can proc both) might come out ahead at higher gear/Vengeance levels.
This is especially possible now that Revenge has started falling behind a bit. It was always a thought in the back of my mind that the new version of War Academy could possibly make Impending Victory a lot more viable.