Totally agree. Before the Studio 68c, I have a ********* U-Phoria UMC404HD which is less than the half the price, but seems, after all, to have more features.
On the UMC there is a button you can hit to set the input monitoring as MONO, in which case all 4 inputs are monitored separately in mono, or you can press it again to get stereo, in which case inputs 1&2 will be panned hard left and right and inputs 3&4 will be to, so they are treated as two stereo pairs rather than 4 mono.
I think PreSonus should update the firmware so that the monitor button can cycle through 3 modes. Default, off. Press once, each input is monitored in mono, centre panned. Press once again, inputs 1-2 and 3-4 are treated as a stereo pair and panned l/r respectively.