Showstoppers, at least in my definition, is anything that breaks user experience and/'or that is wrong/rather pressing.
Segmentation Faults and crashes get a priority of High, but they need valid reproduction cases; otherwise they are to be lowered to Pending on user input. Code related things also go to High. (Usually, it might be better to let those who know handle it.)
Everything else goes to Normal, except for Feature Requests, those go to Wishlist.
Tasks that require more information, etc get changed to Pending on user input.
Merging tasks : I usually merge new tasks into older tasks — unless the newer task has a better reproduction case, etc.
enlightenment18 is dead, tickets will never be handled.