Whilst I see all the benefits of electrification, one of the disadvantages, is that it uses money than then can't be spent on other priority areas. In the case of the West of England line, would you prefer to spend the money on more double tracking or passing loops? I certainly would, if it makes the services more resilient.
I would hope that now double tracks would happen prior to electrification, as once the wires go up then the track layout is much more likely to be fixed.
It's part of the reason why I've suggested that the wires only reach Yeovil and then have one through DMU service every two hours (maybe two every three hours or one every hour if there's 2tph to Exeter) with the other services requiring a cross platform change at Yeovil to an EMU to/from London.
As that would give time to build more double track west of Yeovil and could also give time for the wires to reach Exeter from Reading, which would then mean that there's a business case to wire up the local services as well. Which then splits the costs of the wires at the junctions in Exeter between a few projects. It could also split the cost of the grid connections and/or allow power supplies to come from other lines.
Although it would be a bit of a coup for the WofE line to have wires to Exeter first, it would mean a lot of extra costs (including wires to the sidings) which otherwise could be split.
It also allows there to be thought as to if there could be through trains to Okehampton, or (in time) even Plymouth, as even just a couple of peak hour services could make a big difference, especially given the current services from Barnstaple don't really serve morning commuters heading to Exeter. Given that the 08:23 to Waterloo starts at Exeter it could be possible to run that from Okehampton without the need for extra stock.
