Dang it all, Lee, now I have to change my shorts! :-O
I have long suspected that those who dismiss flat fields probably haven't lived with them too much. Flat fields can be great assets when, as you say, whale watching. They are also great for scanning flocks of peeps for something unusual. And I won't soon forget looking over flocks of Common Terns on Cape Cod in search of Roseate Terns (as it "terned" out the Roseates were pretty easy to find since most of them were banded, and there was a researcher there with a big scope recording the numbers...but you get my point).
Flat fields are also great for just looking over the distant terrain. I was reminded of that recently, out in the Rockies, while trying to catch up with a far-distant Prairie Falcon that might have gone unnoticed without a flat field. If it had been a brown blur out at the edge, forget it.
The key though is that the field has to be "usable." I mean you have to be able to look at it. This is where the SE fell short, for me anyway. Nice and sharp all the way out, but you couldn't get close to the edge without the whole thing blacking out. For me, this was the revelation of the SV. You can USE it, or at least a lot of it. I once described it as a "roam around" view, and although big exit pupils help in that department there's something about the SV eyepiece that takes it to the next level. As evidence of that I can say that the Zen Prime eyepiece is not quite as good in this regard.
So when you compare the SF and SV, do us a favor and see how much of the field is usable. Let your eyeballs wander. I suspect Zeiss has done their homework in this department and that the results are really nice.
Mark