The ExCeL was for feedback but it would never had made any different as the deal was sign and construction started some six months earlier.
Seat back tables weren't included due to modeling showing the 1,000 people on/off couldn't be achieved with them.
The survey was done by Passenger Focus prior to DfT specification asking what was wanted on the units. Key points requested was more seats, arm rests and tables. I had a link a while back and will look for again but totally ignored in the Specification so wasted really.
If the trains couldn't have seat tables and arm rests in the tunnel section then they should have been confined to short high density metro routes and not sent on long distance services to Brighton, Peterborough and Cambridge or even middle distance services like St Albans, East Grinstead, Tattenham and Horsham.
Many commuters on these train use the commute as an extension of work time, but the tight cramped seats on these trains means you won't be able to get your PC out or do any work.
I had the pleasure of travelling from West Brompton to East Croydon tonight on the latest 377/7 (my first time on one) and yes the seat was a bit hard but the space was OK for working at the table, I got quite a bit done and didn't have to cuddle up to the large guy next to me - we had enough space to keep apart.
First time I've not changed at Clapham and I was very surprised to see that the busiest station for getting off was Norbury not Balham as I had expected.