I remember that in the past you just can't work with my variables at all.
Lexcial variables (my) were introduced in Perl 5.000, in 1994 - in fact, Perl 5.000's 26th birthday is in two days.
... my attribute can't be stripped at all. So this is a clear deficiently. ... the debugger ... is indispensable for debugging complex programs.
You seem to be implying that the debugger can't handle lexical variables in the programs one is debugging, which is not correct. The debugger, when used as a REPL, has a few limitations - but it's a debugger, not a REPL. If you're looking for REPLs, see e.g.: