Gliders take the cloud on the left, other aircraft take the cloud on the right. How hard can this possibly be?!
Where I fly (Sweden), large areas of restricted airspace are set aside for soaring in clouds, in the most ideal soaring locations of the country, from 5,000 ft to FL195, during the summer season. Everyone else has to fly around it when the area is used for soaring. Works perfectly, and I hear no complaints.
The British way of mixing everyone in the same cloud seems rather irresponsible IMO, not because the risk is big, but because it is left solely up to chance. On the other hand, demanding that gliders are fitted with all sorts of horribly expensive electronic gizmos only to reduce (not remove!) a 0.nothing risk of collision, can hardly be taken seriously?!
Much better then if powered aircraft are not mixed with IMC gliders at all.