Clear plastic viewing windows on the spring terminals are the way to go. It allows for both instant feedback for the installer, and visual inspection or troubleshooting later by a third party.

The spring terminals should also be designed to have a secondary latch on this type on (what should be) rugged installation.

Finally, critical circuits should be designed to detect open connections, and act accordingly. A single hardware<->software design for this could be a module to apply across all such wiring inputs/outputs. This is simple and cheap enough to do these days.

A manual tug-test on the physical would be advisable when installing, to check the spring terminal has gripped the conductor when latched.

Clear case on the terminal blocks could be nice, though might still get a bit tough to see when you have multi-level TBs all mounted in strip on DIN rail.

When I used to be involved in control panels I would always yank on all the wires too :-)