It's clear that a transaction fee market for will develop, for better or worse. But what about mempool growth? And are there other backlog issues? The stress tests came and went, but we might be entering a sustained period where transactional demand exceeds the networks capacity. What will this look like with nodes and network we have today?
The Core Devs are working on a solution for the mempool issue (in fact it has already been merged to the master branch). This fix will officially be released in 0.12 sometime in early 2016 (feb I think). Basically the fix limits the mempool size and it will drop the transaction with the smallest fee in order to keep the mempool at a certain size which can be user defined.
Currently, the only fix is to change the minrelaytxfee which will prevent transactions under a certain fee and dust threshold from being accepted to the mempool and from being relayed by that node.