Well, I didn't know of this Weekend First change until last night, when I discovered it on the FGW homepage.
I've made my views on the refurb countless times before, but the long and short of it is that I find Standard Class quite reasonable and First Class no longer has the appeal of wider and seemingly more comfortable seats due to the plastification of the supposedly leather seats.
Based on that much alone, I have no real issue with the price change, and in some areas it's going to be cheaper due to it only being a fiver and the restriction on complimentary items appears to have been removed.
What I do have an issue with is that even Virgin don't charge this much. NXEC charge a lot I believe (twenty notes as of December 2007) which I thought was a rip-off. FGW charging 25 notes for the full journey from Paddington to Penzance is a very large increase though and too much. 20 notes would have been the highest I'd be willing to pay for that, and only very begrudingly.
Granted, the allowing of having the upgrade throughout the journey and not just one leg is a plus though. Not sure where that would be useful for me personally, but there's bound to be passengers who will benefit.
I did find it humourous that Westbury to Portsmouth and Brighton is included on the zonal map, yet these routes do not receive any First Class provision from FGW!
Overall, for some passengers this change is good news and on most journeys I do personally on the network it is only a fiver more on top of the previous upgrade (15 notes vice a tenner) which coupled with the chance to use it on the whole journey and not just the HST I travel on and the removal of the 3-items-only rule on complimentary stock may well actually get me using it again. Probably only when Standard Class is wedged out mind, but we will see.