Okay, given how poorly my last prediction went, I'm a little hesitant at making another one. But, thinking about the fixture on current form.
But, looking at the upcoming games for the Waratahs, I can't see them losing another game. Reds have it somewhat tougher with Reds v Stormers and Hurricanes v Reds as possible games they might drop. I think that if they keep up their current form they're a red hot chance to win them though.
Looking at the Bulls and the Stormers, I'm inclined to think that the Bulls will win every game except the last one against the Stormers. I think the Stormers will win every game except for perhaps the one against the Reds.
That leaves the Crusaders. I don't think their tour will be pretty. I think they'll probably drop at least two games, maybe three. The game versus the Brumbies is a big test more of if the Brumbies have recovered their mojo by that point. Especially since its an away game after a tour, it could go badly.
In considering all this, I think there's a very real chance of a Bulls, Stormers, Tahs, Reds top 4 this year, listed in no particular order.