I've actually switched between all different elements, usually after I found a piece with a specific elemental bonus. My first weapon in RoS was a Fulminator so I went lightning; soon after I got Magefist so I went fire; at some point I just wanted to go Archon so I crafted arcane bracers and went arcane. Yesterday I found an Ourobouros with lots of frost damage so I might go frost today.
"Which is more powerful"? Of course they're all powerful. It's not like one element is "better" than the other. It all comes down to gear. I really recommend to just try all of them out - I actually don't like to stay the same for more than 2-3 days, it becomes boring at some point.
I've actually switched between all different elements, usually after I found a piece with a specific elemental bonus. My first weapon in RoS was a Fulminator so I went lightning; soon after I got Magefist so I went fire; at some point I just wanted to go Archon so I crafted arcane bracers and went arcane. Yesterday I found an Ourobouros with lots of frost damage so I might go frost today.
"Which is more powerful"? Of course they're all powerful. It's not like one element is "better" than the other. It all comes down to gear. I really recommend to just try all of them out - I actually don't like to stay the same for more than 2-3 days, it becomes boring at some point.