When the Very High Frequency timetable was being planned on the WCML, with the Norton Bridge upgrade to follow, HS2 wasn't really envisaged. The plan was probably at some point to run another 2 fast paths off Euston each hour to what we have now (xx33 xx37?).
However, HS2 planning has accelerated so quickly that we are now being told phase one to Birmingham and Rugeley WCML link will now be open in 2026. Nothing significant is going to happen now before the end of this West Coast franchise, other than the 3 new off peak Blackpool returns.
So realistically by the time the franchise is re let as West Coast partnership, and the new operator has settled in, it's going to be 2020 and only 6 years of very high frequency west coast running left. And the new franchisee also has to plan for HS2, as they will be running the trains on that for several years once it begins operation.
So it remains questionable whether the two extra fast paths on the WCML will ever be used by passenger services. The operator may commit to introducing bi-mode trains of some kind for use on Chester and North Wales services. However, this may be a problem in itself as there are no off the shelf tilting bi-mode trains available that we know of?
Or another option could be to run the Chester service in the xx33 path with an IEP bi-mode train at 110mph, and let the following Manchester service overtake at Milton Keynes (which is what GNWR want to do with the Blackpool service).
As for extra stops at intermediate stations, nothing is likely to significantly change in the short term. One or two of the Trent Valley stations may claw back the odd stop here and there in the peak or just outside of it, particularly Rugby like with the VT Blackpools.