Peter Woit is worried that particle theory is in trouble, since very few theory papers have made the top 50 most cited list since 1999. According to Peter,
Even more so than last year, this data shows that particle theory and string theory flat-lined around 1999, with a historically unprecedented lack of much in the way of new ideas ever since. Among the top 50 papers, the only particle theory ones written since 1999 are a paper about pentaquarks by Jaffe and Wilczek from 2003 at number 20, the KKLT flux vacua paper at number 29 and a 2002 paper on pp waves at number 32.
How many more years of this will it take before leaders of the particle theory community are willing to publicly admit that there's a problem and start a diiscussion about what can be done about it?
It would seem Peter is living in a different world than me. The problem isn't new ideas, it's the ability to test them which is lacking. Particle theory, particularly of the phenomenological bent, is actually pretty active. Just off the top of my head, here are three very new, very active ideas people have had in particle physics in the last couple of years
1) Split supersymmetry
2) Little Higgs models
3) Warped fermions
Search the arxiv for them, you'll get lots of results. Of course, without an experiment to tell us which new idea is right (or, more likely, that they're all wrong) none of them will get hundreds of citations, but that doesn't imply a lack of new ideas. In fact, it's quite the opposite, there are too many new ideas!
Now assume the LHC turns on and finds solid evidence for option number 2, a little Higgs model, then you can be sure that the original little Higgs papers will rocket up the citition list. Until the LHC turns on, though, we're stuck in a "propose a model, explore some of its consequences, move on" sort of mode. That's precisely the sort of thing that leads to lots of new ideas, and not a lot of citations.
My advice to those who think particle theory is in trouble, read hep-ph on a regular basis :) Of course, particle theory could well be in trouble shortly, it all depends on what the LHC sees, but for now, I'd say it's really quite active. Certainly more active than 5/10 years ago, when there was pretty much SUSY, in the form of the MSSM, and nothing else.