The Seed magazine has asked a couple of physicists what they expect from the LHC.
Lisa Randall and Leon Lederman believe that the LHC could reveal the explanation of weakness of gravity, and Lederman also thinks that it will solve all astrophysical problems. More concretely, Sir Martin Rees mentions the identity of the dark matter that should be clarified by the LHC which could very well be the case, especially if dark matter is composed of the lightest superpartner. ;-)
Steven Weinberg proposes that the LHC will only see Weinberg's restroom, also known as the (single) Higgs boson - a scenario that terrifies many particle physicists. Edward Witten also says that the structure of the electroweak symmetry breaking sector will be the only thing that the LHC will teach us.
John Schwarz believes that all things like monopoles and strings exist, but the LHC won't see them although he might be wrong.
Alex Vilenkin thinks that the absence of supersymmetry will indirectly prove the multiverse, and I find such an assertion extremely controversial. Lenny Susskind says something similar - the only answer we will get is supersymmetry "Yes" or "No", and for him, "No" means an anthropic fine-tuning of the Higgs mass.
Max Tegmark is, much like your humble correspondent, irritated by 26 dimensionless parameters of our current theories that we can't explain. But it is not clear to me how the LHC will exactly explain their value without an additional theoretical breakthrough. Sean Carroll gives no answer - or a universal answer that we don't know and ignorance is the beauty of science. In my opinion, this is the worst among the answers because anyone could give this answer to any question in science.
Gordon Kane offers what I view as the best answer. He thinks that we have evidence that the Higgs mass is comparable to the predictions of supersymmetry. Supersymmetry will likely be found at the LHC, and the LHC could even establish string theory. If at least a part of these goals are realized, the obnoxious critics will finally be annihilated and we will have the freedom to move to the remaining "why" questions.
Gordon Kane's prediction might be wrong after all, but among all the answers, it maximizes the product of "excitement" times "good motivation". Others either give overly speculative predictions that can't really be realized, or un-salty un-oily predictions that would not be overly interesting and that could have been made 35 years ago.
We will see. Even if the LHC modestly illuminates the composition of the Higgs sector, it will be interesting enough because it will show us that theories such as the Standard Model can have a very large domain of validity.
Via Not Even Wrong