Yep, as I was scrolling back through the thread, I noticed the "born" gaffe. +1 for pointing it out.
Regarding receivers slipping and falling, etc., interceptions that result from such situations could be either the fault of the quarterback or the fault of the scheme. If the quarterback throws the ball after the receiver is already out of contention, it may well be the fault of the quarterback. On the other hand, if the play is a timing route and the quarterback has already released the ball when the slip occurs, it's probably the fault of the scheme. (This is one of the many reasons why schemes based heavily on timing routes annoy me -- they're not adaptable to split-second changes in conditions.)
Perhaps a suitable compromise would be analogous to a sack/fumble situation: When the defense drives the quarterback backward such that his momentum is stopped (or they tackle him), the result is a sack. However, if at the same time he loses the ball, a fumble also results (two statistical categories in one play!) and assuming the fumble is lost, change of possession ensues (a third statistical category). Extending this analogy to interceptions, an interception that results from a receiver falling or running the wrong route could be logged as an incompletion followed by . . . whichever term was chosen for such a situation (receiver-failed-to-complete, interception, etc.).