[non-Moose base class implementing -somefeature pragma]
    <- [Moose-style base class adapter passing through -somefeature pragma]
        <- [broad range of subclasses that inherit from Moose-style base class, and that may or may not want to invoke -somefeature]

##</code><code>##

package NonMooseBase;

sub import {
    # I'll spare you the treachery.
}

...

1;




package MooseBase;

use Moose;
use NonMooseBase;
extends 'NonMooseBase';

...

1;



package MySubclass;

extends 'MooseBase';
use MooseBase -somepragma;

...

1;