How did J.J. Thomson's 'plum pudding' model describe the atom? What was its major flaw?

Thomson's 'plum pudding' model proposed that the atom was a sphere of uniformly distributed positive charge, with negatively charged electrons (like 'plums') embedded within it. Its major flaw was its inability to explain the results of Rutherford's gold foil experiment, particularly the large deflections of alpha particles, which indicated a concentrated positive nucleus.