Also, whilst 3+2 seated VEPs were used in the past, they were the exception rarther than the rule, the rule being CEPs and CIGs, and for some time 442s, all with 2+2 seating, tables etc. Before that were the CORs, also 2+2 seated, so historically Portsmouth has always had 2+2 seated "Intercity" trains, and it's only been recently when 3+2 seated Outer Suburban trains have been put on the route. As is mentioned in the report, Southern and South Eastern use 2+2 seated Electrostars on similar length routes (to the Sussex and Kent coasts), and whilst 3+2 seated trains are common on that sort of route north of the Thames, in most cases alternative Intercity service are available, at least for the bulk of the journey.
Also, I think TOCs are beginning to realise that 3+2 seating isn't popular on any services, with people often choosing to stand rarther than squashing on the middle seat between two people (and it's not just fat people who have a problem, what about the poor person who is squashed between two of them).
Since the 442s are unlikely to come back to SWT, and therefore the 444s are unlikely to return to Portsmouth, perhaps a reasonable compromise would be to refit a dedicated fleet of 450s with 2+2 seating and tables, like the 350s used on the WCML

)). By the way, 365s doing London to Kings Lynn and Peterborough also have 2+2 seating, well 3 out of 5 isn't bad.