The thames valley relief changes are interesting to say the least - I do think it's extremely disappointing that one of the Elizabeth line services is curtailed at Maidenhead off-peak when Reading has had a local stopper to London every 15 minutes for a long time - as someone who frequently does Reading to Ealing it is a big disappointment especially since I find the 387s a lot better than the 345s for this journey anyway (tables, not mainly sideways seats and plug sockets). Plus, there still isn't technically a full service, since there are no trains from Reading/Slough to Shenfield, and as mentioned earlier, Shenfield only has one train every half hour west of Paddington
Interestingly also there are no terminal 5 trains down the abbey wood branch, they all form from terminal 4 (since heathrow express has terminal 5).
Seems to me that in the compromise between serving every possible routing, and having an even timetable, TfL have decided to lean towards the latter
Have also seen that a didcot stop has been removed from one bristol per hour and put on the Oxford terminating service, which is probably a good idea imo since that oxford one no longer has a slough call so it doesn't make much difference overall, but then Oxford to Didcot still has 2tph of stoppers as well - personally since from what I've found the vast majority of this traffic is end to end, it would be worth reducing to 1tph since the fast train can cover the other hourly service now, and have it evenly call at all stations (or perhaps like alternate Culham and Appleford) - I think this would only release one train but it also majorly reduces the number of trains turning around at Oxford which often causes delays.
For heading west from Didcot, the remaining Bristol and the Cheltenham are quite even heading away from London, but then from Swindon to Didcot it is a 10/50 split which is quite disappointing