Its a great area to walk, the section between Craven Arms and Llandod has been an area, which has given Mrs BWW and I great pleasure. Big problem is the connectivity with the stations (reqest stops), all to often one gets dumped on a nasty section of B road, you have a traffic experience, which blows the whole pleasure of the day.
Once tried a Country Walking route, where the author of the route thought that a length of the B4356 was suitable for leisure walking. A perfect recipe for missing the train connection at Llangunllo station, a free ride to the nearest mortuary slab would be more likely. I met a German lady on the nearby Black Mountain, she was walking Glyndwr's Way, she asked me for comments on the route and I pointed out that there were some better sections though they were not served by rights of way. Her reply was "vat are zey (landowners) afraid offf, zat I vill take zere land back to Bavaria".
A little bit of trespass is all that is needed to correct some anomalies, sadly I do not think this project will be bold enough do more than cobble together a route out of existing RoW's and bits of highway, here's hoping they have more sense than country walking magazine, who published their route a few months after Open Access came into existence and a perfect and safe alternative was possible.
There is sadly a downside, those who want such pre-prepared route may be lulled into thinking that they have walked that area, whereas they will have only touched a small part of an area even the locals can get lost in.