THe FE is exacltly the solution to your problems :
3 times cheaper and still have very good performances, but yes less than FW. And the equipment is lock until january 2010. With this class who is more accesible to everyone, you have differents contries who can do Formula. With out this class that will be impossible.
So is perfect to have very high level in FW particulary in senior class and FE for beguiner and all people who want have pleasure at a resonable cost. FE is a very good step to FW. Both class will win a lot like this.
For the F158 is completly out of the game compare to all the Formula Windsurfing you can found on the market right now. The big difference is in light wind and strong wind.
Slalom equipment change a lot since 3 years, and come back in competition with the new rules F42, because whe can plane earlier, so less race are cancell now. Organiser can invest again in slalom and this is really excellent.
The important point is to satisfy everybodies from beguiner to really high level.
All the best
I have nothing against FE; but there is none around here, and they've limited it to 11.0 meters, so it's essentially a juniors or lightweight class.
And I don't like Slalom 4/2: lightwind slalom is boring.