There would be tremendous overhead to adding such a feature. It is also not very good programming. If you already have ten scripts modifying the same global variable, then why not create an eleventh that does this...
Code:
alias startChecks { .timerChecks 0 1 checkVariables }
alias checkVariables {
  if (%A > 100) { /echo -a * Variable $1 is now at value $2) }
  if (%Monkey > %Flying) { /echo -a * Cool Monkies can fly!! :) }
}