Sounds like the D(a)fT has found yet another way to screw over the East Midlands then...
It's becoming harder to treat people seriously who can't spell DfT properly...
There are relatively few sensible uses HSTs could be put to work on. They are relatively slow to accelerate, even when reduced in length and are totally unsuited to stop/start type work, which is where the likely demand is going to be.
The fast long-distance services will already have been allocated new stock or remain in the hands of their existing stock - e.g. Pendolinos, Cl 800s and variants, Stadlers (GEML) or new bi-modes (MML).
So what does that leave?
Good points.
They are going to struggle for a home in future (regardless of costly modifications to keep them going).
Great trains in their day, but it's nearly 2020...
If only one of EMT or XC can have bi-modes, then XC is by far the better option; EMT can be the "22x shop". Apart from the morning Nottingham-Bournemouth (and possibly a couple of other odd services), all Voyager services travel at least 81 miles under the wires on each journey, with some doing 250+. If these proposed bi-modes could be fitted with 3rd rail equipment for use in the south there's even more of a case for XC.
There's also the fact that XC bi-modes could use the still-possibly-happening Oxford-Leamington-Coventry and Leeds-York modernisation schemes, while there are no plans for anything extra EMT could use.
London-Kettering is only 73 miles. EMT's units might spend more time under the wires than XC, but even then it's probably fairly marginal
I'm not quibbling the maths, but it's worth remembering that some Voyager diagrams spend hundreds of miles away from the wires (e.g. Edinburgh - Aberdeen - Edinburgh, Bromsgrove - Plymouth - Bromsgrove*), whereas an EMT diagram can see the train doing Kettering - London - Kettering several times a day (especially those on Nottingham services,
assuming that we are talking about after Corby is wired).
I don't know the diagrams, but if Nottingham - London - Nottingham is a four hour cycle then one train could do that six or seven times per day (i.e. 7x73miles).
(* - yes, there'll be a tiny section at Bristol Parkway, but that's not worth splitting hairs over)