I think it could be either Joubert or Plushenko. If Plushenko comes back, then I think he would need a 4t/3t/3t to win over Brian Joubert and others without question,
I don't think this is completely true. For example let's look at these season. I won't count Olys scores because I will be the first to admit (and I'm a huge Plush fan) that Plush was overmarked in his FS, and also a little in his SP.
Plush hasn't done 4-3-3 for COP so his COP marks are actually marks with one quad.
Joubert's best SP scored is 83.64, the one he did at Worlds. And this scored is lower than three previous scores of Plush, the one at GPF in China, his Tosca CoR and his Olys SP. Now ok so the SP has the same elements and I imagine Plush's scores better than Joubert due the PCS marks.
Their FS, Joubert's 3 quads CoR program scored 160.13 (his personal best at a FS), now I remember the three quads but I don't remember much more so I'm assuming he didn't make any other mistakes, and Plush has beat that score with 167.40 that he had at the GPF in Beijing (he scored 167.67 at Olys) and I don't think he was overscored at all at the GPF, he was truly brilliant there and that program had just one quad.
Joubert's best total it's 240.85 and Plush has beaten that score four times, three if you don't count Olys; and from those four times just once (the Beijing GPF) he was completly clean.
So, really by reviewing their scores, I don't think Plush will need a 4-3-3 to win over the new Joubert; I actually think just with one extra quad he'll do it. And sometimes, just doing the same he has done last season will be enough.
Overall comparing to the rest skaters, the only one that has come close to Plush was Takahashi's NHK performance, and that score even Takahashi has said that he knows he was overscored then. IMO he wasn't in the SP but he was in the FS.