The quick slant as a staple of the WCO offense declined considerably as the 3-4 defense and zone-blitz schemes adjusted to take it away. The left OLB, to a right handed QB's right side, and left DE are well schooled now to react to the 3 step throw in the slant's throwing window. The LB stepping back into the WR pattern is particularly effective because it threatens a huge hit on the WR and deflected passes that can lead it INTs. In Rice's later years you saw this as a key defense against his inside slant routes - where his YAC was taken away and he was often subject to bigger hits on this route.
To adjust, it seems to me that when slants are called, more slants are now thrown with the WR split further out to get the throw further out of the clogged inside throwing lane and route lane.
[ Edited by HearstFan on Oct 27, 2012 at 12:32 PM ]