I would not call Perl/Tk outdated.

The major difference between Tk and Tcl::pTk is that Tk embeds a ported version of Tk that does not require a Tcl interpreter, while Tcl::pTk embeds a Tcl interpreter which, in turn, uses a native Tk extension. It is worth noting that the Tcl-free Tk port used in Tk has also been adapted to other languages; if I recall correctly, Python's tk module also uses it.

The Perl community is generally very much in favor of TIMTOWTDI and deriding alternatives to your chosen solution is unlikely to earn you any help.