Having several feet of mono on the end doesn't seem to effect the sensitivity of the braid enough to matter, and with a good splice it doesn't seem to effect the cast much either.
I prefer braid for almost any fishing, and using a mono or fluro leader makes sense for several reasons. Braid seems to me less resistant to abrasion than mono, if for no other reason than it's thickness. Braid is more visible which matters in some cases. Mono's cheaper, in fact cheap stiff mono makes good leaders, so I don't mind trimming away as it gets frayed. And probably most importantly for me, with eyesight and dexterity slowly going away, mono is a heck of a lot easier to tie, especially in wind.
(Not that it matters much with crappie, but when surf fishing I'd much rather take a wrap on #40 mono than #20 braid in order to drag a good fish to the beach.)
With some practice the braid to mono splice is nearly as strong as either line. I splice on leader at home where wind and poor lighting aren't a factor. About the only time I tie directly to braid is when I've lost the leader for some reason and I'm too lazy or in too big of a hurry to get back in the water to make another splice.
You just gonna sit there an argue, or fish?
~Claud Ledbetter~