Shadowcraft (web version) has had its 5.4 model updated with the nerf if you want to check for your own gear.
I deeply encourage this. I've done a minimal amount of poking about so far, toying with a single player's gear set within a very narrow range of gear options (upgraded heroic/heroic TF), and got this:
4pT15 + 5.4 gear: Hotsauce @ Stormreaver-US - ShadowCraft
4pT16 + 5.4 gear: Hotsauce @ Stormreaver-US - ShadowCraft
The 4T16 in that specific scenario is now modeling about 10% ahead, so assuming SC accuracy and matched by actual observations yada yada, there are no 4T15-superiority concerns there.
The comparison still gets a lot closer with the AoC trinket equipped:
4pT15 + 5.4 gear w/ AoC: Hotsauce @ Stormreaver-US - ShadowCraft
4pT16 + 5.4 gear w/o AoC: Hotsauce @ Stormreaver-US - ShadowCraft
In that case sample, the difference shrinks to just ~3%-4%, which makes me a little nervous. Although I want to point out the obvious: The strength of both the 4pT15 and AoC depend very strongly on target uptime, so in practice we will see huge variation in their respective benefits from fight to fight relative to T16 and some of the non-AoC trinkets.