I know you didn't quote me, but as I agree with the poster you quoted, I'll provide my thoughts.
I think Miller is nowhere near ready. He shows nearly nothing in regular season NHL games. I find myself surprisingly in the high minority in that thought though.
For Kreider, it's a confidence issue. The coaching staff ****ed with him all year last season. Up and down, up and down. Let him get into the swing of things in CT, and see what that does to his game.
A guy like Haley or Mashinter can come up and contribute on the fourth line. And we're not killing their development by playing them 10 or less minutes a night.
The thing is, whoever gets called up from CT right now to replace Asham (if anyone, remember, he's already cleared waivers this season and was not sent down) isn't going to step right into the top-6, where Kreider would need to play. Playing CK 12 or less minutes a night on the third line isn't what he needs right now.
Let him get 22 a night in CT in all situations.