RE: LE slats and flaps-worth the effort?
I agree... It's deep.
In regard to the photo though, that really is typical. I have many photos of F-16's, F-18's, F-22's, and F-35's, especially in the landing configuration, where the taileron is actually in the "down" position. I've attached a photo of an F-22 and an F-35, as further examples.
One other thing. i was reading another post, which was, paraphrased, "The leading edge flaps won't make much difference on a model". Well... Think about it from another point of view. (See the 3rd image.) If I came here and said, "Do you think there would be any difference between these two airfoils?", I think you can imagine the response. There certainly would be a large difference! As to how useful they are, only those that have used them can say. I'll be putting them on my sport jet in the next couple of months and will let you know how they work there.
I've only used them on two other aircraft. The first was my very first sport jet, in about 1992, which crashed due to a weak taileron linkage, before I had a chance to use them, so I can't say. The second was on an Andy Lennon-ish high wing design I did in the same time period. (with the leading edge flaps built ala Larry Wolfe's instructions, which were published in MAN) and they made a huge difference, especially when combined with slotted Fowler flaps. That plank-wing airplane was a real speed demon with the devices stowed, but would slow to a crawl with everything deployed. Can't wait to see the effect on my jet.