TL;DR
Give roboports 2 module slots, which can be filled with 2 roboports.
This would have the effect of increasing charging slots, but with concomitant increases in power consumption, same as having 2 roboports occupying that one space. 1 robo-module = 8xSlots, 8MW max consumption. 2 robo-module = 12xSlots, 12MW max consumption.
No changes on bot storage capacity.
Further details
In dedicated bot bases, and in areas of high throughput, the limit of bots is usually roboports. However roboports are one of the largest buildings, and very space intensive in the lategame bot bases, leading to thousands of bots waiting to charge.We already have stacking roboports in the roboport power armor modules, which allows up to 96 bots (not realistic to sustain, but that's the cap) to charge on 1 tile that's your engineer.
