We've had regular short formations on Reading services for over a year now. Presumably this will continue until the situation stabilises with all the conversions done.
The short formations before though where just first thing in the morning before the peak time and after 8pm in the evening.
Now there seems to be short formations on any trains certainly after 9am from Reading and also after 2pm from Waterloo for which the services where previously 8 cars trains. These services where quite packed normally when 8 car trains either from or too Egham.
As an example the 09:12 from Reading last Monday was just a 4 car trains and by the time it got to Staines there was very little room, such that when it got to Clapham Junction it was almost to the point that people would have to sit in people's laps that where already sitting down.
I would not mind but there was both some class 455 and class 450's in Clapham yard not being used, so why make the passengers suffer? The 450's will be moving over to the Reading route at some point soon to work the route regularly, while the 458/5 rebuilds settle down on the Windsor and Hounslow routes.