Although no doubt well intentioned, I feel that the newly launched campaign for a definition of misselling is not going to bear any definitive results. You might as well try and define what is good.
In all walks, there are concepts that, although well known and understood, are very difficult to define accurately as good, decent, honest, ethical.
I think on this occasion it is a little unfair to expect the regulator to come up with the impossible.
An undertaking from the regulator that firms will (note, not should) have no cause for concern provided:
a: Clear evidence is provided that the client was informed in writing (whether by key features and/or a report or a reasons-why letter) of the salient features of the product being proposed, why it was being proposed and what, if any were the pitfalls together with a full disclosure of earnings and commission.
b: Additionally, as none of us has the space or facility to keep files forever, there should be a limitation of, let us say, six years, after which claims are not admissible.
I have a feeling, borne out by your list of those who are supporting the campaign, that those who are keenest to see a clear definition want this as a paradigm to ensure that large salesforces can work to a template and therefore require less training, supervision and paperwork.
Unfortunately what many still do not accept is that the days of recruiting someone who can just breathe and walk, supplying them with a rate book and a bunch of forms and sending them off on the road to sell, is no longer acceptable.
Training, supervision and paperwork applied in sufficient quantity with sufficient rigour should, one would hope (and it would be nice to receive the regulator's confirmation) would be the best defence available against misselling.