Tigthening up the timetable may seem a no brainer once all suburban services have gone over to 701, but sometimes this can prove pointless at certain junction/points of conflict, whereby an earlier arrival at either, causes unwelcome changes to connection opportunities, or the advantage (to the service in question) is lost because it has to await (for longer) a clear path through a junction etc.
The schedules as are, may (I stress may) perhaps allow for the need for a separate leaf fall timetable (eg: Up Readings/Windsor's etc etc, start earlier from October to December) to be dispensed with and run a standard pattern TT all year?
The point about drivers adjusting their point to point running times to even out any excess dwell time at specific locations is perhaps a natural thought process, but again, at certain bottleneck points on the network, it is /can be imperative that services run strictly to the times in the WTT, in order to prevent delays to other services at junctions and points of potential conflict. Hence why any additional padding out time, is designated between specific locations. But all of this will no doubt be taken in to account for any future timetable re-write.