Luck with injuries is most definitely a big factor in winning the Super title, but that is interesting in and of itself. To win you need some luck not just on the injury front but also in terms of scheduling etc (i.e. playing certain teams at the right time of the season, when they are out of form, and playing the majority of your hardest games at home). Nevertheless you still have to take advantage of the luck you get and the Tahs did last year. Had the Sharks not lost to the Stormers towards the end of the season they may very well had been travelling to SA for the finals.
The Reds had similar luck with injuries when they won it in 2011. from memory they lost Morahan for the end of the season and Slipper missed the final, but otherwise they had a relatively clean bill.
Pretty sure that the Reds were hit with wingers being injured at one stage in 2011, to the extent that Caleb Ralph played a cameo game. Reds also lost a few fullbacks (Morahan, Lucas), with Lance playing fullback for the back end of the season.
No key players like Genia, Cooper, etc though went down in 2011, particularly at the business end. The Reds forward pack was particularly lucky with the few injuries they had in the year. Luck with key players is what most teams need to win the comp, and the Reds and Tahs both definitely had it.
The Tahs also had some wing injuries early on in 2014, I thought Betham was out frequently during the season, Crawford started the season injured and Alofa was gone for a few games at times.
However, Foley and Beale and Folau and AAC (Adam Ashley-Cooper) stayed fit in the backs, and somehow TPN lasted the season, along with Hooper and Palu (I think he also somehow played the whole season?). All the Tahs really lost in the pack that maybe mattered was Chapman prior to Dennis going down.
For an Australian team to win it this year, I reckon that they will need similar luck with injuries. We don't seem to have the depth that NZ teams do, they seem to cover key players so much better than us.