I kind of touch on this already in this thread.
is it possible... yes. Ive already shown that on the push, midi is just the implementation... it could be anything including gpio/lcd.
you don't do it by adding objects, you do it by accessing parameters directly... this means it works for every patch without additional objects being added.
is it easy...
well once you understand how parameters work, then getting/setting those is not hard, but its still a lot of code to get it to work. and frankly, without an LCD screen its pretty useless for anything other than trivial patches. (it wouldn't really be worth the effort)
whilst I recognise the Push is expensive (if you don't happen to already use it for Live) there could be quite a few other midi control options that people could write 'drivers' for, e.g. Launchpads are cheap. with a bit of 'creativity' these could be pretty good... and have the advantage that many people can use. (look at what people have done with launchpads with Live.)
note: this is also the concept of Axoloti Control, which is still (afaik) planned, but of course Axolotl Core is taking priority.
note: using midi can result in low precision (7bit), unless you take the approach used by push with endless encoders and use relative encoding ... which is extremely cool.