This is pure fantasy, because it depends on the closing down of the Work Programme and all such private-profit schemes, and that's not going to happen. But just suppose ....
Start by ending the WP and strengthening the Jobcentres, with more staff, retraining and more resources; put them into partnership with local councils. They would do the basic stuff where necessary, like CVs and interview techniques.
Now, that £400 attachment fee which the WP providers have been getting. Instead, put that into a notional account for every person who has been out of work for, say, 6 months. The claimant and JCP adviser together decide what needs to be done to enhance the claimant's job prospects. It could be a training course (a real one) up to the value of £400. I know some training costs a lot more then that, but I think you'd find FE colleges and genuine training bodies willing to put together proper courses for that when the money was sitting there. It could be used for driving lessons; after all, so many jobs depend on having a driving license. Any other ideas? It wouldn't have to be spent all in one go.
Of course, if the claimant signs up for something expensive and then doesn't complete it, there would have to be a good reason. But I don't think there would be many defaulters if it was clear that this was genuinely useful. And those outcome payments? Well, they could go to restoring the money which used to help someone bridge the gap between starting a job and getting paid.
As I said, it's not going to happen. Pity.