Looking at what Canon really need to do, there's not a lot, I think.
800f/5.6 II, needed to compete with Nikon's new Lens, and I've seen it, it's good (Nikon's 800 I mean), probabely within the next 6 to 12 months, they have to, no choice for Canon.
35f/1.4 II, needed, forget what Sigma can & can't do, Canon need to revamp this Lens, again, next 6 to 12 months.
135 L II, needed, current lens is a beauty, but Zeiss have raised the Bar, so Canon will reciprocate, maybe 12 to 18 months away.
200f/2 II, hard to judge, how do you improve on perfection ?? but this Lens will probably get the Series II treatment, 12 to 18 months away.
TSE's, Overdue for a 50 & 90 revamp, 2014 for sure.
Man, 2014 looks to be a year to live for, of course we will all be poorer by 2015, but that's like 2 years away, why worry now.