FZ200 f2.8 constant aperture

This is an interesting thread. My question is related, but slightly different:

If the aperture is able to get so large at 600mm, why can't it be as large at 25mm? In other words, the lens could be much much faster at 25mm because the aperture can open so large. One should be able to easily get f/1.4 or better.

I posted a similar question when the FZ200 was first announced.

http://forums.dpreview.com/forums/post/42313350

I got a couple of answers which (to the best of my non-existent understanding of lens design) was that Panasonic could make the lens faster (i.e., larger aperture) at the wideangle end, but that the lens performance would be less than acceptable because of optical problems created by having such a large aperture at such small focal lengths.

However it still seems to me that if the aperture can open so large at 600mm then it should also be able to able to open larger at 25mm focal length and produce at least a a somewhat faster lens at wideangle ... maybe f/2.4 or f/2.0. This would provide a real speed advantage at widewangle.

Any thoughts on why the FZ200 isn't faster at wideangle even though it's aperture can open so large???

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- Simon