Silver Standard didn't work, so I'd say Premium Standard isn't going to work either. I don't see how you'd price it, especially on trains with a high proportion of business travellers who buy the most expensive Anytime tickets.
I'd have said Scum Class would have more chance of success
Silver Standard was in a different time, though. I've long thought the future of First Class is leisure travel and self-upgrading, and those passengers aren't as interested in paying a small fortune with an inclusive meal - that used to work for business travellers because it removed tax implications of paying for an evening meal on a trip where you're returning home that day (and made expense claims easier).
I can't see why in a million years I'd pay an upgrade for the same Standard seat but freebies - I can just buy the freebies myself and have far more choice of what to buy and where from. But I will pay a
reasonable[1] upgrade[2] price for "European style First Class" i.e. just a bigger seat and nothing else. Maybe tea/coffee/iced tap water as those cost next to nowt to provide (hence why MML provided them in both classes), but I really don't mind buying them.
I could almost envisage a situation where "full" First Class actually went away and we return to the land of common sense. What Avanti are doing is basically a "real life" survey.
And of course it's working for Eurostar...
[1] One that tallies with the ratio of First Class to Standard seats in a coach, in other words.
[2] It being available as an upgrade is key for self-upgraders travelling on business - many businesses won't allow the "faff" of people booking First and trying to work out how to offset the difference against expenses - I upgraded myself on work travel in Switzerland a lot more than I do at home on weekdays because I can just get a "Klassenwechsel" from the ticket machine! It didn't take long for sleasyJet to work this out - even if your employer will only book the basic fare you can at check-in add premium seats etc on yourself.