Modify the Effects for Multiple Selected Layers - At Once
Cinema4D's Attribute Panel allows a user to select multiple layers, and modify various attributes that those layers share, at once. After Effects could certainly benefit from this. Could be extended to shape layer properties, etc.
Ludwig Tomaschko commented
PLEASE BRING IT!!!!! This would be awesome... Like Jordan said, have a look at Cinema 4D and just copy the behaviour, JUST COPY AND DONE!
Michael Szalapski commented
That's a solution for if you want everything to be the same, but what if you just want to tweak (not link) one property across several layers with everything else remaining separate?
You can use Copy With Property Links to create duplicate effects linked to an original.
Jordan Quackenbush commented
Say you have three layers with trapcode particular on them. Imagine just selecting the layers, and in the Effects panel you can just change one property on all three by sliding/typing it in. That's it, done.