How could or should the 6.5 mm Grendel be improved?

[stanc]

The 7.62 mm x 39 case is an ideal start point for an intermediate round. But if an extended 6.8 mm x 45 case were used instead, the round would have an even smaller diameter allowing more to be fitted into a standard magazine.

According to my calculations, if we're talking about a 25-rd magazine, the difference in capacities would be no more than one round, at most, and maybe zero rounds. That doesn't seem significant to me.