I'm with metaladdiction about if the plastic worm would slip and scrunch down on the leader after being fished, they main problem of any threaded plastic worm. The threaded plastic worm needs to adhere to the leader well to stop the plastic worm from scrunching on the leader. Hard stiff plastic worms scrunch less than soft limp plastic worms. That is why I do not use a bait threader to thread the plastic worm, it opens up too large of a hole for the leader to adhere to well.

What has worked then best for me to keep a threaded plastic worm from scrunching on the leader. Is to tie a small Uni knot with 1/16" tags with another piece of mono. on the leader and thread leader, Uni knot 3/4 of the way in to the plastic worm. The Uni knot on the leader, allows the plastic worm to adhere to the leader very well with very little scrunching down the leader. This works well with softer limp worms that scrunch easier. I would think the Uni knot threaded leader rigging might work very well with a pre holed plastic worm to keep it from scrunching.

I would definitely be interested in trying out a pre holed plastic worm, good idea.