Hmmm, that probably won't help much, because presumably the class knows who its direct ancestor is. It gets tricky with multiple inheritance and/or deep inheritance hierarchies, where it's just plain hard to tell from a casual glance who the next method is. Note how in this case there's no guarantee $ISA[0] ."::validate" exists.
If you want to do that kind of analysis, though, the code in NEXT.pm might provide inspiration. Or deterrence :-)