I've little to say on Chris Chibnall's appointment as executive producer/head writer of Doctor Who beyond that it will be difficult to judge him on his previous work for the series, none of which established a personal signature. Torchwood was effectively show-run by him for its first two series, but I suspect he was dealing with several competing agendas over what the series was meant to be; I've been told by someone who saw the script that the visualisation of 'Cyberwoman' was definitely not implied by Chibnall's descriptions, for example. Since then he's (re)learned the showrunner's job on Law and Order UK(having been the creator of Born and Bred before Who's return) and then created Broadchurch, of course - I've not seen all of the first series of the latter and wasn't that impressed by the second episode of the second series and stpped watching. However, he knows about the business of television on both sides of the Atlantic and is of course a veteran Doctor Who fan, though one who took no part in the workshopping of the concepts of Doctor Who by the Virgin and BBC Books ranges in the 1989-2005 period, nor indeed (I think) with Big Finish. Indicators to watch will be the continuity with the Moffat era on staffing - the start of the Moffat-Wenger-Willis production era had at least one significant element of competition over personnel with the outgoing Davies-Gardner team - and whether Chibnall contributes to the 2017 series. Otherwise there is nothing one can do but wait and see.