Anakin did things Luke never did-Anakin participated in a full blown war as a General-Luke was more of a Commando, and he didnt even fight that much during the GCW.
they had the force. they were just confined to a subsector of the force not felt by jedi. qas shown by omini controlling shimraa using the force ( he could do this because he insertede yammosk tissue into his brain. (yammosks could use force on vong, as they effectively controlled them in battle.)
defeating lumiya, vader and other dark jedi and sith is no different from what others have done. and shimmra was mad. he was controlled by onimi and when he fled he couldn
Anakin also did great things during the clone wars. and he killed numerous jedi between 19 and 1 BBY. And it isn't sure that the clone dude was really Palpatine. that is mentioned in many sources. And there is always this talk about Luke doing many great things. but he hasn't really done anything very extraordinary. He has faced similar problems like many other jedi before him.
Im with Meyer. If Lucas said their potential is equal then they would have always been equal if Anakin didn't turn into Darth Vader. But if were talking about 'what is' then Luke. Vader never defeated Palpatine. But Luke defeated him (his clone, who was supposedly more powerful then before(Dark Empire)). Luke displayed so much power through out his life, did Anakin even come close to his feats at any point?