I don't think Steve would switch to somthing that he hadn't tested and trained on before a race like the worlds.
I heard that there are some f2 riders that are also ride'n there 06 f2 instead of there 07 f2s.
I think the reason for this is the performace in light vs. heavy conditions. Most 06 boards had narrow tail widths.
These were good in heavy conditions but suffered some in light air race'n. Then in 07 everyone added 3 or 4 cm to the tail. This helped in the light air, but gave up some performace in the heavy stuff.
A plateau in formula board development was, i think, around 2005. After that any changes that were made took away performace in one area to enhance another.
I race FW with two boards. A bic 1.4 for the events that will be held in winds that will drop below 10knots, and the 06 f2 for events where the wind min is not expected to go below 10knots.
It works good for me. The 1.4 is much faster in the light stuff than anything out today. But if the wind picks up I'm at a disadvantage.
Today FW is almost a one design class. use'n and knowing how to use the stuff is part of the race.
I think any FW board from 2001 to 2008 can be competive.