Luke and us (the audience) didn't know Palpatine had lightning (assuming you watched the O.T. first). Heck we didn't even know he could use the Force or his capablilies. Also Luke is a Jedi because he had the training, sure the training had to be adapted to the enviroment but there were no formal facilities at that time. Obi-Wan and Yoda also both trained him and told him that he was a Jedi.
You are correct Anakin is the Chosen One, George Lucas said so.
A shame Palpatine wasn't the only sith lore to use force lighting. Would have made him more unique, and really show how powerful he was.