Here’s a generally excellent article on the current trends of how early Buddhism is conceived, with special reference to the Gandhari texts, and reflecting on how this impacts the current state of things.
My only quibble would be that the author somewhat overstates the importance of the Gandhari texts in this context. Of course they are important, but they mostly confirm previous theories that have been influential in the past generation or two of scholars, rather than overthrowing any orthodoxy.
i think there is no doubt that the basic principle here is true: the Buddhist texts, from the earliest times, existed in multiple variants. In fact every monastic would have memorized the texts somewhat differently. This diverse tradition is engaged with by the centralizing tendency represented by the Councils, which attempted to create a monolithic canon. But at no stage was there ever a single body of texts universally accepted by all Buddhists.
As usual, however, i feel the need to issue a caution in that these findings are often mistakenly assumed to disprove the usefulness of text-criticism and to overthrow the orthodoxy. This is not the case. In fact they only contradict certain of the conclusions of earlier generations of scholars, conclusions which had already been substantially modified by later text scholars. The Gandhari texts are simply one more source, albeit a uniquely valuable one, to help aid our understanding of early Buddhism. In fact, without the background knowledge of the texts established by conventional text-criticism, it would not be possible to really understand what these few texts are and how they relate to each other.