Well for sure the title of this topic is a bit misleading. In my humble opinion attack detection concern is easily addressed.
IMHO the real concerns lie in how the filter opens in relation to the signal's amplitude... Coloscope's exponential mapping is the right way for me, and I tried to implement some sort of omplitude selection that only listens to the upper range of the dynamics, but I'm not totally happy with it.
It's not only a matter of opening a binary gate... make this effect "musical" is a challenge. When I listen to pedal demos videos I notice, among other things, how the filter shuts with note sustain, this is not easy to implement, at least for me