I honestly cannot say. The best I can say is, as soon as all the bugs are worked out of 5.4. These things usually don’t take that long. Like I said, I wouldn’t have even said anything except that anyone that uses another solution now if they could have waited would not be very happy.
Actually, yes, you could use an entire field group as the fields for a “Layout”. It’s going to make life a lot easier for developers that uses the same sequence of fields multiple times.
