The Powercore 5000 is more than double the volume of the Powercore+ Mini.
Is more than double the size a "minimal size difference"?
I agree 2A out is more useful, how much more useful is device dependent, in some cases it is of no use, particularly with smaller and older phones, the lady's purse is an example. In some cases it is a disadvantage such as recharging smaller devices like BT earbuds the cut-off current is lower in the 1A output so it can fully recharge better some things than a 2A.
This is a horses for courses debate. Lady's purse vs trouser pocket, vs bag, etc.