Sample poorly drawn image above. The fan is outside the PSU sandwiched between the PSU grille and another outer grille. The fan header could be exposed outside the PSU. And the entire PSU housing could be shorter to accommodate standard sizes.
PSU fans currently are made to be inside the PSU so if you want to do some maintenance, you have to take the entire PSU apart which is extremely unsafe.
I thought about this idea cause I recently took a very big risk opening up my PSU cause the fan was *extremely noisy* with rattling that drove me crazy. I made sure to drain all the caps of course and took all necessary precautions. Once I cleaned the PSU and lubed up the fan, it was as good as new. No noise anymore and the fan is running smooth.
Fans always get dirty or they may even fail. That's just a basic fact of life. So why do I need to risk getting shocked to death just to perform basic maintenance on my PSU? Can't the fan be outside the PSU housing so it can be easily repairable/replaceable?