You're quite correct, of course, and despite very rarely driving genuinely dangerously, I too have probably performed manouvers (deliberate drifting, high-speed driving, etc.) which, although performed safely (IMO), would be considered "dangerous driving" under current legislation.
Whilst I hold with the fact that "dangerous driving" and "causing death by dangerous driving" should carry the same penalty, I would thoroughly agree that the current definition of dangerous driving is ludicrously lax. If it were going to carry a serious penalty (which I believe it should), it should be only enforcible where multiple officers could testify to witnessing the offender driving in such a way that caused a genuine high risk of injury and possible fatalities, not just because they happened to be diriving 101mph on an empty motorway (which, of course, could cause an accident, but is actually low risk).