Pursuit generally only matters if the type of win is of concern - I guess only in competitions.
Armies using the Send in the Guard rule certainly find life tough without Pursuit cavalry. (But 1815 French Guard can't get Pursuit cavalry, so guess it is pretty irrelevant to them).
I am certainly in the group thinking Organic cavalry support is way overpowered. If in doubt, always take Organic cavalry support. Pursuit is less important.
But I quite like large Reserve Cuirassier units - while they are not on the table for long, they can do a lot of damage quickly, scare enemy cavalry, and absorb lots of hits. I think 2 large Cuirassiers is worth the same as 4 small Dragoons/Lancers/Hussars. I find Reserve small cavalry units tend come on late, take a couple of hits and then don't have time to rally them off and get into the action again. Large cuirassiers just keep going and going accumulating DISR but knocking things over.
Cam