Tracking DoT durations while raiding is key, and these addons would further help me along in the process. While I currently use NECB, the global cooldown bar would further aid re-casts. While text displaying a spell's avail may be overkill, it can only help rather than hinder.

You could possibly try Omnicc, it just is an overlay which sits over your spell button on yoru actionbar counting down until it is ready to cast again. It also does not affect NECB which I also use.