It's an interesting question, and one that cannot be answered simply by analysing souths themselves. There's no doubt that they'll miss Burgess next year. I think Stewart and Te'o cancel each other out. However in the scheme of things, you'd have to say that they'll be a different side next year. Perhaps better, perhaps worse. But certainly different. It's probably interesting to point out that Souths' winning percentage over the last few years without Sam Burgess is actually quite high.
But what must also be considered is where the challenge is going to come from. You would say that, on face value, the other recently successful teams are all, for one reason or another, going to be weaker.
The roosters are without Sonny Bill and Minichiello, who basically have set the culture for that club in the last two years. They are likely to pick up Blake Ferguson, but it remains to be seen whether he'll fit in there.
Melbourne have lost Hoffman and a hell of a lot of depth. The big 3 are getting older.
Canterbury lose Ennis, who was more important to them, than I think they realise. There are also suggestions they'll lose some depth.
Manly- Losing G.Stewart, King, and possibly other members of their core group.
North Qld basically followed the same trajectory that they have for the last 4 or 5 years. And with no real additions to their side (and the loss of Tariq and Ashton Sims, never thought I'd be saying that of Ashton), their pack does not look as daunting at this stage.
One team on the up is certainly Penrith, who'll add Apisai Koroisou to their ranks. Koroisou and Segeyaro are effectively the same player, and could potentially form the most devastating dummy halves combination in recent memory. An 80 minute danger. They're not losing anyone of note, and will be better for the experience this year.
Parramatta are probably the other team on the up, however it remains to be seen whether a Chris Sandow led side, can take that next step. He's got a track record for not standing up, and against the great sides, Hayne can't do it by himself. How Peats returns from injury, and Watmough's impending recruitment shape as the determining factors.
So in conclusion, I suppose the question shouldn't be whether souths can go back to back, but rather, who is going to beat them.