Iconoclasts in cosmology seem to be rather thin on the ground at the moment. Michael J. Disney, however, Emeritus Professor in the School of Physics and Astronomy at Cardiff University, attempts to damage the credibility of the Magical Kingdom in the current issue of American Scientist.
Disney claims that the number of independent observations in cosmology is much smaller than the number of independent free parameters in current cosmological theories, and argues from this that "modern cosmology has at best very flimsy observational support." Seven years ago, Disney wrote 'The Case Against Cosmology', along rather similar lines, making the notable point en route that only "one per cent of the light in the night sky comes from beyond our Galaxy."
However, I don't think Disney has really done anything here other than: (i) re-discover that all scientific theory is under-determined by data; (ii) re-discover that cosmology is a data-starved science; and (iii) re-discover that cosmological theories have to make some rather special assumptions in order to reach any conclusions at all about the universe as a whole. From the emotive language employed, one can detect significant professional jealousy in Disney's diatribe. For example, in his year 2000 paper, Disney wrote:
Much of cosmology is unhealthily self-referencing and it seems to an outsider like myself that cosmological fashions and reputations are made more by acclamation than by genuine scientific debate.
A scientific discipline in which the participants only read and reference each others' papers. Imagine! And in this context, as is oft the case with a scientist writing on philosophical issues, it is noticeable that Disney has made no effort to read or reference the relevant literature on the philosophy of cosmology. That, quite simply, is poor scholarship.