In a break from the whining, here's an Xmas gift, the route to St Werburgh's. This is good quality, though missing a few features that would prevent it being used as much as you'd think. Little things like lighting and signage.
This is a video of the descent from UWE to St Werburghs, following the official path with a few mountain bike options exercised. After all, the quality and intermittentness of the S Gloucs paths do effectively mandate mountain bikes with good travel on the front forks and -ideally- disk brakes. If you have the transport needed to negotiate bike paths whose entry and exits go over undropped kerbs, paths with 50cm dropoffs where the paths meet, etc, then you may as well make the most of it and have some fun.
Anyone who depends on TfL for their cycle safety will stare at this video and say "we wish we could have something this good", but the dutch will look at it and say "Could our children get to school on this?".
This video was taken in October, just as the sun was starting to set during the evening peak commute times. Once the clock changed, this went all dark and even on foot you'd worry about the underpass beneath the M32. You'd also stop using the fishponds roundabout underpasses and use the road crossings. Which, in their favour, are there at all: those over the M32 entry/exit points are recent. Until a year ago there was a sign saying "three pedestrians have died crossing here -use the underpass". Now there is an overground option that is survivable, even if you have to wait a minute or two.
Speaking of underpasses, the stairs are optional. You can go down the slope, though it's a bit skittery when the autumn leaves are there. A direct descent of the (shorter) steps avoids the corner and the traction on a 45 degree flight of steps is consistently bad in all weather.
Once you cross the roundabout you get into the 20 mph zone, with speed bumps to enforce deceleration. Heading out, the pavement is a shared use route, heading in you can grab the lane and head down it before scooting right. Then comes the final stretch to the St Werburgh's bridge, up over that and it's in to St Werburghs. UWE to the city, in under 14 minutes, with minimal risks, at least during daylight hours.
Most of this route is under the control of the Bristol Council cycle team. The good features: the 20mph zone, the give-way crossings, the new bike/pedestrian crossings at the roundabout, the frome valley path are all their work. Presumably the stretch through stoke park is theirs too.
In what is clearly the S Gloucs stretch at the beginning, you can see their official bike path features. Crossings and barriers. No signage saying "city centre 15 minutes".
And all the way along: no lighting. You would be fairly bold to do this on foot or bike on your own.
The biggest irritant is that stretch of road. It's a wide road with minimal parking pressure. Why didn't they put a segregated bike path along here, with some formal crossing at the roundabout? Do that with some lights and you do have a safe path that the kids could use.
The other issue is that the M32 bridge can't sustain heavy bicycle traffic. Two bicycles cannot pass on the corners, and visibility as you approach those bends, especially uphill, is pretty bad. If the volume of cycling traffic increases, this bridge could become a choke point. This would be an opportunity to put in access routes that are wider, and add some lighting at the same time.