When a weapon modifying spell like magic weapon or flame weapon are used on a wildshape with multiple attacks it only applies to one of these attacks. I suggest that they apply to all attacks or otherwise a druid fighting things with any form of DR becomes extremely difficult. This seems like a reasonable enough compromise now that mage armor no longer applies to wildshaped forms.
Drinking blur will give your wildshape attacks pierce +1 DR. Drinking stoneskin will give you piece +5 DR.
Exactly as Pentaxius says, in wild shape there are already significant options for Druids already.
Druid wildshapes are poorly scripted and wildly broken to an unfixable extent, but there are certain tricks like this to circumvent some of the more lame characteristics of wildshape.