I've now read the report in full, except the appendix by L.E.K. which seemed to just be a load of pictures and arrows (clearly the printout of slides accompanying a presentation we aren't party to). I found it quite interesting, but as I don't work on the railways I can't comment on the feasibility of the proposals, however it appears that Mr Gibb hasn't shied away from making some very radical recommendations.
The argument over electrifying the Uckfield line felt quite compelling to me, as I have always felt this diesel stub makes no sense. However I have my reservations about using private capital in this way and having a third party own and manage the wires, and maintain the track on the Uckfield branch. Surely it'd be more efficient for Network Rail to maintain it given they already maintain the surrounding lines? Although OHLE may be more power efficient, quicker and cheaper to erect, it adds a complication with rolling stock having to do a voltage change on the move. Changing power source is something that seems to often fail on 37x stock in the Thameslink core. Overhead power is also quite ugly, so I can't see the local residents lining up to support its installation in the pleasant scenary in which it would be visible. If the ticket prices on the Uckfield branch were to increase at the rate he suggests, to even out the disparity compared to nearby stations served by Southeastern, they might find they don't need so much capacity after all!
A lot of the the solutions proposed involved dumping periphery services onto other TOCs (but not the majority of the Southern Metro). e.g. Milton Keynes - East Croydon and Hertford - Moorgate services possibly going to London Overground so GTR can focus on a smaller network. I'm not convinced that this will automatically make those better though.
Regarding GatEx, I'm glad that an official report has finally said what this forum has been saying all along. The 3 brands strategy on the Brighton Mainline is confusing and its ticketting is confusing, leading to packed Thameslink trains whilst expensive Gatwick Express trains use valuable paths catering fresh air around. I haven't been to Gatwick in rush hour, so I didn't know it had such a profound impact on platform overcrowding though. I still think that the Gatwick Express brand should be abolished, given it now has uncomfy rolling stock.
The overnight timetable reduction in services that was foisted on us with virtually no notice whilst this report was embargoed is too hasty. We should have been given more notice of the change, especially the residents of Coulsdon South, Merstham and Redhill whose overnight service has been culled. I don't think withdrawing overnight services to Victoria is a big deal, but they should have waited until Crossrail opened for interchange at Farringdon, and after Thameslink trains resuming running via the quick route via Blackfriars and London Bridge before culling the Victoria services. At the moment, Thameslink is badly connected to London's nightlife that is more in the West End, and the route via Tulse Hill is slow. That said, as Gibb recommended the trains will be timed to the slowest route, you might end up sitting at Croydon for some time if your train takes the fastest route anyway! If they can support single line bi-di working at the southern end of the BML, why not 2-line working on the 4-track railway between Victoria and Croydon, at least until 2018?
I think he's missed a few things that are screwing up performance though, such as the leisurely dispatchers at East Croydon who appear to have all the time in the world.
The report appears to be written on the premise that DOO has been already decided. I hope that this thread doesn't become another thread about the merits and drawbacks of DOO, as there is already another thread where this was covered extensively. As far as Chris Gibb is concerned, that ship has sailed already.