I'm pretty sure 411's 'spanwise flow' is a red herring in terms of stalling angle of sweptback wings - we really need JF here to correct us all, but I seem to recall that it was vortex generation at the L Edge, parallel to the LE, that re-energised the boundary layer and 're-attached' the airstream, thus permitting greater unstalled angles of attack, along with a widened buffet boundary (a lot of swept-wing fighters spend a lot of their time in manoeuvre in buffet and the BAC Lightning speed on approach could be controlled with a higher AoA producing more 'stall' buffet
) plus, of course, an overall reduced CL/alpha slope.