The 387s aren't bad trains ... good leg room power sockets reading lights armrests tables good windows alignment
.. A lot there to make a good train
Absolutely, they have some good features and would be fine on the correct services, but they are being deployed on services which do not take advantage of the good points and for which they have other features making them less suitable.
No train service with 584 seats already carrying some standing passengers is ever improved in the perception of its passengers by reducing the seating capacity to 447.
Class 387s don't make up for the reduction in seating capacity by providing an internal layout that makes space for comfortable standing and lack the stand-backs that would deliver shorter dwell times. At least the class 700s will have these features, which will be essential through the Thameslink core.
The stand-back is the space between the door itself and the adjacent partition into the saloon. Providing more space here is particularly important as this is where passengers stand first. Without good stand-back space (on 317s or 387s), these passengers become an obstruction to boarding and alighting passengers, effectively enforcing single file on and off.
I know I've said this before, but this change has a material adverse impact on my quality of life. Either I will have get up earlier and get home later, taking the slower trains and losing half an hour per day with my children, or I have to stand for half an hour when previously I could sit. I know other people have long had to do this and I know that capacity has to be added. I plan train services on other commuter routes, so I fully understand the issues! But the fact remains that the 'Thameslink Upgrade' will give many other stations on GN far more 12 car trains to make up the number of seats, despite their having far fewer passengers than Welwyn Garden City. WGC on the other hand will have to lump the same train frequency, not just with fewer seats, but with added stops and a slower run time into London. Not really an upgrade.