If areas that had wet feet early keep getting rains which sounds like there are areas might be too much, any hot spell could be a problem with shallow roots.  Also if rains keep getting heavier and areas get wetter and wetter the chances of top yield can go out the window as well.  Traders in Chicago only think heat and dry take yield, its the sneaky too wet problems only seem to get realized when combines roll.  I feel if there is no summer rally, there could yet be a day of reckoning on lower yields than expected.  Remember national pollination will be a long process this year so hiccups can occur!