I recall Rick Remender stating that Archangel turning into Death canceled out Gambit's transformation into Death. The last time his Death persona made an appearance was sometime in X-Men: Legacy during Carey's run, when Blindfold confronted Gambit about the Death identity growing inside him, and Death took over him for a moment. I'm pretty sure that's the last time Deathbit has been mentioned.
In other words, Mike Carey was building up the storyline but either dropped it or didn't have time to carry it out. Gambit also being Death didn't fit into Remender's plans (or he just couldn't bother with it, as he's openly stated that he has no interest in Gambit) so he ended the whole plotline in interviews.
In other words, Gambit got better, and Death is dead - unless some future writer decided to pick up the plotline.
Personally, I never cared much for the "Gambit as Death" plotline, so I'm not sad to see in go, even with a whimper. I didn't find it particularly compelling, and I think battling with his Death persona hindered Gambit as a character. It just never promised anything of interest.
Although I do recall someone here at the Comicvine forums suggesting that it would be cool if the Death persona got somehow separated from Gambit and turned into its own individual being & became Gambit's new nemesis. Now that would make a wicked story.