Avatar Question: Are the benders in Legend of Korra overpowered?

It seems to me that in Legend of Korra every bender can perform all the skills only the most gifted of benders were able to in The Last Airbender. Especially lightning.

It is a highly dangerous and precise technique, but they use it to power machines.

Zuko nearly killed himself when he tried to create lightning, but now all these benders are able to do it easily? And there are also many chi-blockers. One or two would be fine, but that many?

Now finally to the question... Do you think the normal benders in Legend of Korra are overpowered? Or are the skills lowered to make it more interesting? I think they are too strong in general.