I can foresee several complaints on the replacement of 387s with 345s , even when they are extended to 9 cars. The 345s may be good metro trains but they’re still metro trains, with high standing ratios, nowhere to store bags or umbrellas, no toilets and large door apertures - which may not be such an issue on the underground sections, but you would certainly feel it in a windy December day at Taplow.
My OH regularly travels from Reading to Ealing Broadway. She will now be taking the GWR into Paddington and travelling back to Ealing, which is about the same time-wise but more expensive. (There are no GWRs stopping at Ealing during rush hours, despite what has been said elsewhere on this forum)
Estate agents in Reading are always citing the ‘Crossrail ‘connection as a positive selling point, but I don’t think it will offer any advantages to Reading residents, even when it is fully operational.