I have to say I'd enjoy a jaunt around Kinder on the bike Jon, but only limited sections are viable as "horseable" bridleways, horses up there would be a menace, and in any case would struggle to get up, (Jacobs ladder? Grindsbrook???) So the horse brigade are unlikely to be in favour. That said, the vast majority of over eroded paths are over eroded because of regulations sending every bike, motorbike and horse down the same narrow route alongside the walkers. I could come up with my own definitive map of "sensible" trails for the bikes, but I'd ideall like the whole of the national parks to be declared open country and fair game to horsers and bikers. New routes would soon appear where walkers go, leaving many more miles of bikeable tracks and reducing pressure on the current, horribly restricted, network. Getting walkers out of the "bloody biker" mindset when someone rides withoutg attention to others and into a "bloddy idiot" mindset instead is very very difficult. We can all do little things, as riders or as walkers, either to think a little more about other groups or simply to present ourselves better as bikers (like not discarding inner tubes about the place) chatting to bikers/walkers when you meet makes a big difference, and the mood on the hills is noticeably friendlier towards bikers compared to 5 years back.
The main problem as ever is the RA's stubborn unwillingness to bow to any changes which don't directly benefit them, ramblers mass protests were a great step forward, but MTB's on footpaths are unwanted nature wrecking nightmares, not true and not fair, and as more of us realise the enjoyment to be had from both, the less the view that wheels=bad will prevail. In ten years we'll be biking where we want, I hope, and ALL groups will benefit, whether they know it yet or not.