The 319 cascade has now reached the stage where Liverpool-Manchester via Newton-le-Willows could be electrified 2-3 years before the cascade starts. At a Northern stakeholder meeting it was suggested that if the London Midland 323s get cascaded to Northern then they will replace all EMUs in the West Yorkshire area with the 333s going to Manchester for Liverpool-Manchester and the 321s going to National Express East Anglia.
Platform extensions are the main issue.
One of the things that might happen though is that the Triangle receives an allocation of 323's to help it boost capacity on certain stretches.
Leeds-Bradford and Ilkley-Bradford/Leeds could all be made into self contained diagrams with 3/6car units, whilst the Skipton-Leeds/Bradford could have to remain 4 car to combat the issues with Shipley P2 (Skipton bound) and P5 (Bradford - Skipton) not really being long enough (and very little space to give anything more than an extra carriage at best
There are plans to install a Keighley turnback and run longer services in the peak to Skipton. By bringing West Yorkshire this allocation, the 321/9's could be sent somewhere to help with another TOC because some 333's could be allocated to Donny services
One possibility is that Manchester could receive a small fleet of Dustybins from Scotland and West Yorkshire but that idea has not raised its head yet. This would be post Olympics so the 322's may actually come back up from East Anglia.
Of course nothing stops a larger 323 fleet being allocated alongside an 8 or so strong 321 fleet on Leeds - Keighley and Skipton - Bradford turns and 323's operating to Donny and Leeds - Skipton semi fasts.
The fleet could be made even smaller if the Carlisle services were made hourly (highly unlikely according to NR).
It will require even more money to extend platforms (with Saltaire, Crossflatts and the Doncaster route requiring money to extend platforms).
The other issue is what will boost the Manchester EMU fleet? 16 4 car units for 17 3 car units doesn't really work too well.
I have discussed it in great details with colleagues and we are currently with the belief that although there are many great ideas, the status quo will remain with the 333's and it will be the 321 fleet that will move.