BEagle - In hindsight, I realise my response may have appeared slightly derogatory, which was not my intention at all. I merely meant to suggest that the theory you volunteered, when proposed to a ppl student, would not allow you to come to the conclusion I was suggesting. Not that it really matters. I would volunteer your exact same explanation every time. Apologies
Interestingly, LE devices are indeed more complex, but also have a far more profound effect upon the lifting characteristics of aerofoils. It is quite revealing to look at the procedures one has to follow subsequent to Flap/Slat jams on large jets. In my experience (perhaps you could chip in with your wealth of knowledge BEagle), large jets can generally land at slower speeds when flapless than they can slatless - slats significantly increase the AoA an aerofoil can achieve before stalling. Incidentally, when landing with flap jams, the pitch angle on approach tends to be very high leading to a probably, if not definite, tailscrape!
Rgds,
Cuban_8