USB ports or sockets for every seat is now a basic requirement for intercity services. Battery packs are helpful but not enough if you have been out for too long, especially with a tablet. I doubt the cost of installing them on Pendolinos would be huge. Free wifi is the same, at intercity prices its a reasonable expectation. People can do without either but shouldn't have to on an intercity service.
Out of interest, what do the East Midlands Trains HSTs (mk3s) have? Do they have plugs or USB sockets retro fitted?