The popularisation of mountain bikes has resulted in the mass destruction of the surfaces of many routes by the vandalism of mountain bikes.
Sorry but I've never heard such rubbish! Mountain bikes cause practically no damage whatsoever. Why must you immediately try to turn this into another "us vs them" topic? Can't you see you're actually better off banding together to improve these assets?
I despair at the terrible state of bridleways around here, but I'm quite confident that's down to poor drainage and poor upkeep. Most of them (good examples around Roman Lakes and Strines) seem to have sadly become streams rather than pathways, with water completely washing away the surface, especially with sudden heavy rains in recent years. In some cases, new surfacing has even been laid only for it to be completely washed away! We need a major programme of installing proper drainage channels along these routes to ensure they aren't lost forever.
Edit: In the final "suggest any other improvements" I put:
"Resurfacing Middlewood Way between Torkington Lane and A6, plus providing a proper link across to SEMMMS A6 link road, allowing residents of Marple to quickly and cleanly access this major new cycle route. Major programme of drainage channel improvements to bridleways around Strines, Roman Lakes and Marple to fix longstanding issues of surface wash-away. Working with Canal and River Trust, resurfacing terrible (in parts) Peak Forest Canal towpath from Marple to Stockport border and promoting as the "green gateway to the Peak District" for walking and cycling."