it appeared that perl/Gtk dropped ATUOLOAD mechanics during GTk binding, and this means that huge amount of perl subroutines is created at startup, which are mostly never used, just pollute symbol table.

This is a shame, I can not believe people program this way nowadays.
Perl is fast, convenient, and doing huge amount of needless work at startup is just not the way to go.

Developers said they feel autoloading is not very stable, and - what they decided? let us, users, pay for their inability to efficiently program?

This is just not acceptable.