In one of the articles that discussed the Luke's kids rumor, it said that Lucas and Arndt fought against it and Lucas relented because it was JJ's film.

I don't think Lucas is happy with the change at all. He spent years working on the prequels and the Clone Wars. He was essentially done with the OT and its characters in any way. It was only when he had to sell the company that he came up with something. And those ideas are now being thrown out by JJ and Kasdan and thats why Arndt left.