Unless they put him in a good angle leading to a world title shot, having Kane wear his mask would be completely pointless. In the last 2 years wearing the mask as a face, Kane was boring. Teaming with RVD and X-Pac was stupid. However, after he lost the mask, and went on the psycho rampage burning people and whatnot, he was interesting and kind of scary. As a babyface, Kane really sucks. He's flat and dull. But as a heel, Kane shines.
A good storyline to put the mask back on would be him as a face against someone like Kennedy or Chuck Palumbo. Kane loses an inferno match, but looks like he dies and gets completely burned to a crisp (Takes some time off for knee surgery). A few months later, someone starts decimating everyone, on all three shows, but nobody knows who it is. Then, during one of Undertaker's matches, Kane interrupts with new music, a new full-body costume, and a new mask (no hair though; that would be stupid). Kane destroys the Undertaker, which sets up a feud between the two. It culminates at Survivor Series in an Elimination Chamber. Kane wins a number one contender ship to Edge's Championship after eliminating almost everybody. He DESTROYS Edge at Armageddon to win the World Heavyweight Championship. Feuds with Edge until Royal Rumble where he retains and Undertaker wins the Rumble. The stipulation for Wrestlemania 25 is whoever loses is required to retire from wrestling forever. Kane loses, Undertaker is champion, and Kane is inducted in the Hall of Fame for 'Mania 26.