I agree with some of what your saying but the assist cut threshold is there so we dont get classed as low powered mopeds (UK)
As a cyclist we have free access to everything at least in the UK they will not alter it to go higher theres to many aresholes and do-gooders that dont like it as it is ,
Next it will be a License ,insurance ,log book with registration plate and approved helmets at minimum will be required if it went higher
Potentially Mots and lights horns etc where does it end

Also you will only be allowed to cycle on the road No where else a cyclist can go including trail centres, bike parks , bike lanes etc
I could go on but we all no this and the 15.5mph isnt going to change if anything they will knock it back down at least here in the UK to where it was it doesnt matter how much we go on about
And dare i say its the idiot element that will stuff it up for everyone as per usual anyway .