PCB design considerations for running 48 stepper motors
The "thick wires" have less inductance than thin wires. 100:1 ratio is 1500nH/m while 50:1 ratio is 1000nH/m


Litz wire has much lower L and comes in many strands and AWG of enamel wire.


With all these stepper surge currents and dead-band half bridges, it will be a CM noise nightmare for any high L or C impedance coupling to stray input cables or tracks. 

Recommendations


CM chokes on each pair to raise the CM impedance with optional shunt caps or ferrite beads for DM mode suppression.  example SMD CM Choke 200mA &lt;1ohm
Twisted pair cables, shielded, if bundled.
fault sense on open connections 
Datum (aka Home/End Stop) opto Schmitt inverter sensor feedback on same CM choke twist pair for immunity. depending on cable length and arc noises nearby.
low ESR caps to shunt RdsOn/Coss current spikes
0.5~1.5us Dead time depending on loads L/R ratios etc.
model your circuit design for EMI control including DCR, R distributed C on cables and cap ESR vs C
use accelerated pulse rates for slew control factoring Motor torque and inertial loads to obtain max speed and avoid skips or cogging at all costs.
include cogging current sensors in case of unexpected stiction
slots are generally efficient EMI antenna and bad if rise times &lt;&lt; 50ns nearby


(Disclaimer) This is by no means a complete DFM list of recommendations