There just isn't any room there for Swanboats in that area unless you plan on ripping most all of the trees out (which it sounds like you are when you mention turning that third of Adventureland into the English countryside.) This would be terrible for the Jungle Cruise, which needs them to help hide the rest of the park. I'd like a little boatride, Swans or not, but I'd like it to be similar to the DL Storyboats, maybe even with a Casey Jr. Doing that would put it firmly in Fantasyland, which is where this belongs anyway.
Setting everything else aside I really do like the attraction as it is. It lets you walk through at your own pace, giving you a great view of that area of the park, there's no obnoxious line (which is good for those of us who don't get the opportunity to visit Fall/early Spring after the crowds have died down.) The Magic Kingdom needs more things that you can just do, you know. Finally, I don't really care about boys vs. girls or whatever but Pixie Hollow is something that skews extremely young by Disney standards. I don't even think teenaged guests would know what it is unless they have a younger sister whereas most people should at least know the recent Disney films or get the broad concepts other aspects of the park are based on.
I suppose I should note that I am in my mid-twenties, have seen SFR but don't regard it as a childhood staple or anything, and don't hold the attraction up as a must keep in the way some people do for some things.
If I were the head of Disney, I would keep in mind when making a ride, movie,etc. I would want the target market/demographic to be described in one word: "Universal". I understand that some rides/movies lean towards one focus group more than others and that's fine, but they should not be the entire focus for the whole itself. The best thing to do is to make it as relateable/enjoyable to the most guests possible and go from there.
