Yeah as much as I'd love to see a followup to SR, and see the relationship with his son explored further, it's getting to the point where the kid actor is going to be too old to make the idea even worthwhile.
I mean there was already a big gap until Superman met him the FIRST time; by the time we get to continue the story, we'll be looking at a 10 or 11 year old version of that kid.
I'd love to see where Singer wanted to go with it, too. And I don't think that the kid getting older would necessarily be a bad thing, as I'd always envisioned the story moving forward in that way, picking up on where he and Supes were at years later. Kids do grow up.
But...the vibe I'm getting from what the TPTB are saying in the quote in the OP is that their idea of a new direction would be to drop the kid angle. And since that was Singer's baby (pardon the expression), I doubt he'd be willing to play ball, and thus he wouldn't return.
I think we're looking at some sort of reboot here; whether it's an all-out origin movie or not, whether it gets right off the ground or spends a decade or more in development hell. I don't think we're getting Singer or SR2.