Left to themselves, VT would not run to either Blackpool or Shrewsbury without new tilting stock being available, or they will have to steal some from other existing WC services.
There will be a net increase of 2x390 next year when the H3 upgrades are finished, but nobody has confirmed what new services they will be used on.
Best guess is the "10th path" Euston-Preston calling at Crewe, Warrington and Wigan and allowing the Glasgows to run non-stop to Preston.
Some of these could continue to Lancaster or Blackpool, but would need 57s if introduced to Blackpool before the wires are up (May 2016).
But this needs a timetable revision to be agreed and there are other competing priorities for the paths.
At one time it was supposed to follow the Norton Bridge remodelling (which increases capacity through Stafford) which is not confirmed yet in CP5.
The very simplest way to start a train from Blackpool would be to send the current 0535 Lancaster starter (221) to Blackpool instead, but that is hardly likely to placate the politicians or locals.
Another way would be to use the extra 390s on Birmingham-Scotland services instead and displace a few 221s for a Blackpool/Shrewsbury service.
And if you are not careful you will replace a current 11-car 390 from Preston with a 5-car 221 and annoy another lot of people.
I'm not sure Blackpool can currently handle an 11-car 390 (maybe not even a 9-car, or a 10-car 221), and the intermediate stations certainly can't.
The Blackpool setup will of course change after electrification, but the solution for Shrewsbury will have to be long-term.
As VT are now on a management contract the costs of new services will lie with DfT, but I don't expect there is an open cheque book.
They would probably plump for new mini-Pendolinos with new locos off the wires, but that won't happen before the next full franchise.