Again, we have a meta-study that has looked at all of the available evidence up to ~6 months ago, and has found no strong evidence that DBS is a promising treatment option. Better devices to achieve the un-promising treatment won't change that fact, not significantly.

Since Parkinsons is for now an incurable and barely treatable disease, it makes sense to try even things that are not very promising. But that doesn't mean we should hold out much hope for them, when all evidence suggests that they are not going to pan out.

Your points are all things that the authors of the meta-study should have looked for, or irrelevancies (anecdotes of people feeling better at some points after they underwent major neuro-surgery are entirely irrelevant to the complexity of a very slow acting degenerative disease).