No, it’s unfortunately not.
Maybe I’ve misunderstood something here what you guys are talking about, but at least in Logic as host you can control its transport (like PLAY/STOP) regardless if any other AU plug-in window is focused or not.
Redux behaves like this too but only while the editor is collapsed (not when it’s uncollapsed). So, I guess this is rather an intentional design decision rather than “technical reasons”. I suppose for some users this is exactly like they want it to work though, but it’s a workflow-obstacle to others if they’re used to plug-ins to not override the host-transport (which more often than not is the case).
This is my main-issue with Redux. I’d be happy if it was possible to at least optionally make Redux “bypass” the space key in future updates, so new modifications in the phrase editor efficiently and quickly could be tried out out along with the Logic arrangement (meaning without having to un-focus the Redux-window each time for PLAY/STOP). If needed, the SOLO-button in a DAW is there for a reason too.
This was also what we were discussing inthis topic, but you didn’t follow up when I mentioned that’s not a normal behavior of a plug-in.