Simplify the following text for a Grade 13 native English-speaking person.
Original: Furthermore , the producers wished to bring back the character of Walt Lloyd , however Malcolm David Kelley , who portrays Walt , had aged significantly and the producers were unable to overcome this obstacle .
Simplified: Furthermore , the producers wished to bring back the character of Walt Lloyd , however Malcolm David Kelley , who portrays Walt , has aged significantly and the producers are working to overcome this obstacle .