If such a "heavily refurbished" requirement is to be expected for those Class 321 and Class 322 units to go to the future "Anglia" franchise, will the same "heavily refurbished" specification also apply to any Class 319 unit sent to the new "Northern" franchise to replace them?
Not necessarily. EMUs on the GEML, like most of those on commuter routes in the south-east get very heavy use. In most cases, on long lines without diversion loops that are full of trains on minimum headways, breakdowns can cause costly major disruption for the rest of the peak period, so great steps are taken to reduce the liklelyhood of such failures where that additional cost is a small price to pay.
Compare this to the 319's easy life in the north-west, where breakdowns can usually be dealt with fairly easily with the possible exception of Castlefields to the throat of Piccadilly.
The minor failures experienced to date with 319s in the NW have mainly been down to OLE problems and the maintenance learning curve so in a cost-sensitive environment, the 'refresh' was probably the right decision. They are clearly more reliable than the 350/4s when they first arrived so they aren't anywhere near their end of life.