I'd love it. When sequencing external gear routed through the OT and using the cross-fader to manipulate internal parameters, it just gives this great desire to have access to manipulate parameters of the external gear from the same control.
What I could get by with and should be possible: scene lock ability for depth and speed of the midi LFO! This should limit the stream and the programming required. The midi stream would be limited because there would only be a max of 3 parameters scene lockable per track and you would give up an LFO for each. Scene-locking the depth of a steady-state LFO, designed in the LFO designer, would give the same effect as scene-locking the parameter itself.
I don't think a petition is needed. Elektron HQ does listen to user requests. Many user ideas have made it into the OS of their machines. As stated on the front page of this forum, if you want to make an officially "heard" request, fill out a support ticket on Elektron's customer support page.