Nucleophilic Substitution vs Single Electron Transfer

The nature of the SN2 itself is focus of discussion since a simultaneous transfer of two electrons (equation (a), "classical" SN2 concept) may be also interpreted as a two consecutive one electron transfer (equation (b), Single Electron Transfer, SET)



Traditionally, (Single) Electron Transfer reactions are discussed in terms of Outer Sphere and Inner sphere. In the Outer Sphere cases, there is no significant structural modification along with the reaction coordinate during the Electron Transfer. In the Inner Sphere cases there is a significant structural modification on the reaction coordinate (typically a bond breaking in reductions and/or a bond formation in oxidations or substancial modifications in bond angles synchronised with solvent reorganisation).

Then, the classical SN2 concept and the Inner Sphere Single Electron Transfer one are very similar in meaning.

Do we really need keep on looking at them through the prism of the classical two electron shift concept?