FME Desktop includes limited options to customise the interface to support people with impaired vision for example, other than alterations to the font.
I frequently work with colleagues and customers with some level of colour-blindness and the ability to discern the difference between a red and green attribute port arrow, or a transformer parameter button, or a featuretype connection arrow (the main offenders) colour is difficult or impossible. This means that 'issues' in the design or setup of an FME Workspace can often be overlooked with the resulting data problems.
This makes interesting reading regarding some of the challenges:
http://www.colourblindawareness.org/colour-blindness/types-of-colour-blindness/
The ability to apply a blanket colour change to some of these port colours would be very handy I'm sure.