I am sure you have Titanium Backup installed. It can remove the whole app easily . But make sure, you have set the Go Launcher Ex app as the default homescreen app.
Thanks a ton. I uninstalled both "Nova Launcher" and "Android Launcher 4.1.2" through Titanium Backup (already had set "Go Launcher" as the default). My phone now feels more responsive and smooth than before now. Also took out "Go Task Manager" because the built-in Task Manager for 4.1.2 is in itself efficient and good at killing tasks and freeing up memory.
P.s: I think we should have a seperate thread for Android related discussions. We are hogging this thread with all these discussions.