To be honest they have a number of ex-Mexican talent on the roster. I always thought if the company seriously got behind Kalisto he could have taken Rey's spot. Hell why not do this...
- Pair Kalisto/Mystrerio as a tag team. Have them win the RAW World tag team titles and have a nice run awhile. Build Kalisto to be on Rey's level. Turn Rey Mysterio heel as he keeps hearing how Kalisto is the new young lion and how he has to be happy to be with him repeatedly. This makes Mysterio turn heel on him and Mysterio can proclaim , "I was the original , the greatest masked talent the WWE has ever seen and now its all how great you are Kalisto ! How awesome you are..."
- Have them collide at a PPV and let Kalisto go over. You basically build and create a new Mexican star.